We fish (and catch) a lot on the fly in Guatemala; if you are not concerned with IGFA............then I would recommend
a) Shorten the flyline to about 20ft (from the back obviously)
b) attach an offshore/wind on leader as it gives flex into the line
e) 18 ins. of bit leader
as the prior poster said, loop to loop works well also, particulalrly if you have to shape a leader to be able to cast...............most people (including me !) can only cast a cam sigler popper about 30ft with a 12wt, so am more concerned with flex and a decent leader to give the mate something to hold onto when the fish needs holding to the side of the boat.