Yes I'm sure a few people will wait to see if my gearbox blows up.
Not sure if the latter suffix gear would work, remember they were a matched pair, anyway I think 0.77 will be fine as it's been tried and tested in a few vehicles. I'm building what is a new gearbox really. All gears will be replaced apart from 3rd which was perfect, new synchro hubs, mainshaft, input shaft, layshaft, synchro rings, bearings and seals. Quite a few TR7 Leyland numbered parts are no longer available so I'm fitting Land Rover parts such as the synchro hubs, layshaft and 5th gears, it expensive and time consuming but I don't trust anyone else to rebuild it. Just check compatibility before fitting, the defender 1st/2nd synchro has a wider gear but that's okay as it'll match the layshaft. Be prepared to shop around, so far I've bought parts from the UK, Italy, France and the USA.
In addition to the issues I've mentioned above check the width of the bearing you are fitting when setting up for float measurement. Rather than following the dimensions given in the manual for the dummy bearing, there may be a slight difference, mine was 0.4 mm less. Our apprentice will be helping out so I should have quite a few pictures by the time it's done. I'm just waiting on the 2nd gear to arrive from the USA and then I'll just need two more original Synchro rings and that'll be it. It's difficult to find useful info online as most information skips over the blood and guts issues I've mentioned and just repeats the obvious stuff. Unless you've found answers to my questions?