I will preference my statement here with "In my experience".  Take that as you will.  I am a Laurel in the 'research, construction, and use' of missile weapons and archery gear.  I have spent more than half my SCA 'lifetime' involved as an archery officer.  I have even spent a term as Society Deputy Earl Marshal for Siege, integrating with the other combat missile officers in the SCA and in kingdoms as part of the job.  Probably 18 years or more as an officer involved in archery of some kind.
So here's my take.
Better?  Maybe, maybe not.  Depends on your criteria.  You are correct that technically the thin shafted arrows have longer range, better accuracy, and you can carry more.  If that is your criteria for being better in the mixed field game, then by your criteria thin shafted arrows are better.  But if you factor in elements that are not specifically technically about the ballistics of an arrow, you might reach a different conclusion, and sacrifice a bit of accuracy and range for gameplay more suited to the desired outcome.  So subjectively it fits what we want to do better.
You are also right that our system was designed by heavy armored combatants. It was engineered to increase the ability of archery to integrate into the Calontir battlefield, and a side effect of that was to limit technical effectiveness of an arrow, but that was not the primary design intent.  The limited effectiveness of some aspects was the result of compromise to reach other desired goals.  Since we do have a rather old-fashioned notion that each person on the battlefield in armor is actually a heavy armored fighter, and that means that anyone shooting archery on the field is a heavy armored fighter, then I put it to you that our archery system was designed (by archers and non-archers all of whom are heavy armored fighters) to follow many of the same requirements of any heavy armored weapons system.  Has to be effective but not nuclear, has to be able to be acknowledged, has to be safe for the whole field, has to integrate completely with existing armor standards, and in our case has to add more to the overall fun than it takes away.  
When you can send an arrow accurately across a battlefield from one end to the other with a 30 pound bow, that is not historically accurate for most battles with a major involvement of archery.  I suspect that in percentage of battlefield area in which an archer would be directly effective (point of aim shooting) the larger arrows are more representative of the historical reality, being able to accurately range only about 40-50% or less of our average battlefield with any kind of accuracy.
I suggest that we can deliver a harder blow, easier to acknowledge in heavier armor.  We can use a heavier bow, more realistic in the effect it has over time on the archers.  We don't need any special armor for anyone to participate, watch, or marshal.  Our arrows are easy to identify, they don't need constant re-inspection, and they are inherently safer.  Our arrows materials can be sourced locally by anyone, and built without special equipment or skills.   It makes the game easier to participate in by our standards, and creates what I consider an adequately dangerous and effective archery force without archery becoming a nuclear weapon.
So consider it what you will, technicalities aside.  It is a best fit for us, so we consider that in the name of the game as we play it it is preferable.  Others have a different opinion, and they play the game they feel best suited.  And if a better fit for us comes along, we will adopt it.
And you know, while there are a few details to building a heavy arrow, there are not many things that can be written technically.  As for tactics and best use and that sort of thing, well, since most of the types on the field that actually practice Calontir combat archery have some background in hunting and sport archery away from the SCA, they simply learn to shoot what they have at the same types of targets that they would engage with another system.  I have seen and been involved in a LOT of Calontir combat and siege missile weapon activities, and I can't say that we make significant use of any other historical precedence or developed archery tactics except ''it's wearing (insert opposition tape color here), shoot it, and if you miss and it gets too close then hit it with a stick."  Target priority being the same in a battle, archers just might have a few more options to engage the priority targets.
Not exactly Floregium stuff, but it gets the job done for us.
And those, if there are any, with a more developed sense of tactics and authenticity with our gear will, I am certain, be happy to provide all kinds of information.

> On Jul 28, 2013, at 3:54 PM, Clayton Neff <[log in to unmask]>
> wrote:
>> Kaz spoke truthfully when he said:
>>> You can carry as many as you can be safe on the field carrying,
>>> and you can pick up from the field as you go.
>> However, be aware than gleaning of arrows is allowed for Calontir
>> legal siloflex or golf-tube arrows only. If you participate in
>> combat archery at a foreign war, and they are using thin shafted
>> archery, then those arrows must be re-inspected before they can
>> be used again.
>> One more reason our solution is a better one.
>> -- Logan --
> I might agree, if the golftube/siloflex arrows could be shot
> accurately or for any distance. They're distinctly inferior on both
> these counts to the "thin shafted" archery practiced in most other
> kingdoms, from what I've seen and heard.  Their much bigger size,
> limiting how many can be carried with you, is another disadvantage
> of the golf-tube arrows, IMHO.
> From what I've seen the golf tube/siloflex arrows seem to be
> something invented by the armored foot soldiers to limit the
> effectiveness of archery on the SCA combat field.
> I think most of what I have in the ARCHERY section in the
> Florilegium is about the "thin shafted" archery. I would welcome
> some articles, including construction details, about these silo
> flex arrows. I leave regulations and such to the official sites,
> but I would welcome how-to articles, including how to use these
> particular arrows tactically or strategically to their best effect.
> Stefan
> --------
> THLord Stefan li Rous    Barony of Bryn Gwlad    Kingdom of
> Ansteorra    Mark S. Harris          Austin, Texas         
> [log in to unmask] http://www.linkedin.com/in/marksharris
> **** See Stefan's Florilegium files at:  http://www.florilegium.org
> ****