BeastOfTheEast,
I will try to answr the questions directly, from my (actual NOT armchair) expierences.
Question 1- What is the most reliable build of a 7.5 pistol....what componets?
I have shot the Model 1 Sales (M1S for short) 7.5" A2 & Flattop units and the CMMG Inc. 7.3" Flattop unit, and from my expierences, with an Aimpoint CompM on the flattops and a TruGlo 2X30 on a Gooseneck on the A2, after a couple of mags, I & everyone else there were hitting soda cans out to 150 yards consistantly (we were in a gravel pit). We probably could have gone further, but we were limited by the space available. The M1S Flattop, the owner opened the gas port just a little before the first mag was done because it was not cycling completely, after that mod it worked flawlessly. The M1S A2 unit worked flawlessly after changing the Buffer assembly out to the "New Style" Pistol buffer. The M1S Flattop unit had the Pistol Buffer tube from RB Precision as did the CMMG 7.3" Flattop unit. I would use either the H3 or a 9MM Buffer. I've read about the Endine Buffers, but I have not used or even held one I use the H3 Buffer myself. I also want to try the Tungston Bolt Carrier Insert to add some more weight to the Bolt Carrier. All three units fired had M16 Bolt Carriers.
Question 2- How much reliability can I expect?
With my CMMG 7.3" Flattop unit and the H3 Buffer, I get 100%, same as my friends with their M1S units, after their mods. If you get one of these short units and it doesn't work 100%, this board is the Best Place to get info and ideas as to what to try next!
Also upgrade your bolt with the Defender Extractor mod.
Question 3- What is the benefit of a Noveske FS ?
My friends have the early Noveske US Krink Flash-Hider, and they make it ALOT nicer to stand side-by-side shooting these short barreled Pistols (Beasts). They point the concussion forward, not outward. My CMMG 7.3" unit still has an A2 Flash-Hider(not for long), and you don't want to stand next to anyone firing this unit! You stand back about a yard, and make sure you/re wearing Shooting Glasses or Googles! I almost forgot WEAR Hearing Protection, PERIOD.
I hope this helps. Whatever you try as far as these 7.5" units, if it doesn'twork right the first mag full, read this Pistol Board, espeially the Buffer section at the top. Lots of good info here.
Chief