Before you commit to a C6 tranny consider your options. I have a built up C6 behind my BB Ford and a 2.75 rear gear. I don't like the highway cruising RPM's. The stall converter recommended by the engine builder which I have is a 2600. With the huge amount of torque my engine delivers I'm still running at 3K+ on the freeway, leaving me short on cruising pleasure as well as MPG's. Also the high rear end causes the car to behave in a less spirited manner than I expect at low speeds. I have been considering switching to a 2200 convertor as well.
I'm giving serious thought to converting over to an AOD with lockup torque converter which would drop my cruising RPM to 2200 +/-. If I then change to 3.55's I can have a more spirited launch along with still allow for cruising at the original RPM's. Right now I have the best of neither world. Tom Wells drives a C6 and doesn't mind the RPM's at all, so maybe you wouldn't, I don't know. With an AOD I could at least choose much more relaxed cruising or fun quick launches.
BTW I too have difficulty using a clutch (size 14-15's plus many ankle surgeries) so a manual setup which would sort out all these difficulties isn't in the offing for me either.
Regards!
Dirk
P.S. I just revisited the Gear Calculator page and sure enough my VDO speedo is STILL way off. (I've set it many a time and after failing to get it to run at more than 1/2 my actual speed had a shop adjust and set it on the DYNO...I'll check it with my GPS soon to be sure)...my gears calculate to 2700 at 75MPH and would just drop to 2400 with an AOD at 75MPH BUT that would be with 3.73's, making QUITE a change in my low speed responsiveness!
