WOW! That was a lot of typin
When I was doin the research for my swap I wound up with the following reasons to go with the Richmond and not the other tranys I was considering (mainly the T-56, but I was considering others as well).
The Richmond is based on the old Doug Nash 5 speeds. The gears are huge straight cut pieces, NASCAR style and bullet proof. The shifter connects via external levers and shift rods, fully adjustable. The Richmond is rated at 450 ft/lbs. You can get different ratios. I have a 3.28 1st and a .76 6th. My buddy has a 3.01 1st and .62 6th. Richmond can make one from .9 to .5 overdrive. Very minimal ?clearancing? of the tranny tunnel crossmember needed. Can use a Scattershield (readily available). 5 true gears and 1 overdrive gear.
I was told ONLY the Viper T-56(.50 6th) was rated at 450 ft/lbs. Some places modify the bearings and say 450 ft/lbs for all of them.
The T-56 is HUGE. The shifter would be located about 6" farther back than the stock location. It requires massive tunnel mods (which is no prob for R100RT because he is really making a one of a kind car). The shifter is internal and is prone to sloppiness and breaking. The bellhousings available are just aluminum bellhousings re-drilled. At the time there were no scattershields available, but I guess you could have one fabbed up. The one D&D makes is ?cast? just like the stock bellhousing. A cast bellhousing will not be much of a help if your clutch fails. The T-56 is basically a 4 speed with 2 overdrive gears, didn?t seem real practical to me (one overdrive gear is good enough).
Basically it came down to this:
Richmond is stronger than the T-56
Richmond had 5 true gears 1 overdrive, T-56 4 gears 2 overdrives
Richmond has more readily available parts (scattershield, hyd bearing, etc?)
Richmond has stronger shifter
Richmond required less cutting of the body/ tunnel cross member
Richmond would have better shifter placement in the car
As far as final RPM keep in mind that depending on your cam you could go TOO LOW on RPM. Make sure you are still within you RPM band for you cam whichever setup you go with.
I made a program to calculate MPH/RPM/Gear so I could make a wiser decision on which trans ratio to go with. Here are a few using some of the specs you posted. If you want other charts (diff trans ratio, rear ratio, etc) just let me know.
Richmond .76 od
Richmond .62 od
T-56 .62 final od
T-56 .50 final od