Rob I found my Gipro w/TRE excellent, acurate and very fast (no delay). As for size I was told by many people behind me that they could see what gear I was in.
You'll find it very easy to mount with your knowledge and should take about 20mins all up. I didnt have to program mine on the gumby but Firey did when I installed his.
I bought a non TRE Gipro gear indicator for the tracky as I felt I wouldnt use the TRE on the track (I am riding wrong if I did need it:oops: ). So far I have installed it but having troubles with the programing phase of it. The direction state it shouldnt need it. Anyways I have emailed the guys below and they are soughting it out.
I have bought a few things off them and they are pretty good. They are also the only distributer for Healtech in Oz
http://www.amcmotorcycles.com/let me know if you need more info