"the range was 800 yards so there aint anyone telling me that in the hands of a good shooter a short barreled gun cant run right with a long one."
Yes that is true. The key being "good shooter".
" if your front sight is 1/1000" off on a 4" barrel it will impact the target twice as far off as it will with 1/1000" off and an 8" barrel. This is a fact, nothing to do with how well it balances or how easy it is to carry or how well you see the sights."
That also is true. The real reason that longer barrels for most people are easier to hit with...the longer barrel does not amplify errors in sight alignment as much.
Bottom line, as Lloyd said...trigger control is the single most important issue in hitting with a handgun. Shooting from a bench is a great way to learn that, as is shooting a gun with a heavy trigger pull. I actually have a few that I leave with heavy pulls, and when I start missing, I go back to them. I have to "re-learn" good trigger pull at times and those guns are great teachers.
To the question asked, for the Bisley I really like the 5 1/2" best. It carries easy in a Milt Sparks holster on my belt, easy in and out of the pick up, not in the way. The 4 5/8" is a close second. I usually hunt with a 7 1/2" in a shoulder holster, because I like a shoulder holster when I am hunting. (Bandoleer type)