CONGRATS! on building your first trainer! You have gotten lots of very good tips. I have built a few trainers and the one you picked out will be perfect.
I have flown the LA s and the other OS motors. I have used up a few LAs but still own and fly the 1988 OS FSR ABC .40 that was my first RC motor.
if you go LA go for the 46.
When you get to covering SAVE all the backing! It is the best to build on over plans, also save some the little pieces of covering for patching.