Really late to this post, but here's an opinion.
First, I agree that Triumph transmissions are too close! For the flat-tish torque curve of the engines - expecially the 800 - a much wider transmission (-25% 1st, + 20% 6th, and spread in-between) would be great. That would make the transmisison harder to package - oh, well. Not user-adjustable. Next option.
While it is fun to increase acceleration by reducing the gearing - bigger rear &/or smaller front sprocket - the only real useful impact is to reduce 1st gear so you can go slower at higher RPM. That is not terribly useful. Also, reducing the overall gearing tightens up the transmission too (as in, where a 4,000 RPM range may have translated to 40 MPH spread in a gear before, it will now only be maybe 35 MPH).
So I opt to go the other way - am going from the 16-50 OEM gearing to 17-47 (a 13% change to taller gearing). In 1st, the same RPM that used to be 15 MPH will become 17 MPH - only 2 MPH faster. Not really a game-changer.
BUT - in 6th gear, the same RPM that was 75 MPH will now be 85 MPH - or, thinking the other way, 6,000 RPM at ~80 MPH becomes 5,520 RPM. Much less busy.
If I find the acceleration to sluggish in 6th, I'll shift to 5th or even 4th. Whatever. NOTE: The transmission intergear-difference between 5-6 is 9%; it's about 13% between 4-5. So my change makes:
+ the new 4th is the same as the original 5th,
+ the new 5th a little taller then the orignal 6th,
+ the new 6th is a much-taller cruising / highway gear.
In the low-end, there is a 25% difference 1-2, so the new 1st is about halfway between the original 1st and 2nd. Since I can pretty easily start out in 2nd now, that won't be a problem.
I've made the - for me - mistake of gearing down previous bikes (Speed Triple, Trophy, another Speed Triple) - only to feel it too busy at highway speeds and to then go the other way to taller-than-stock gearing.
Just my 2 cents.