[Schwag]

for the anti-reverse, a good trick is to put it in place and then turn the bevel gear until the AR clicks into the next slot. Most times the tension will keep it in place. Moving the end of the spring down flat against the box helps too, as mentioned earlier.
For the trigger, lay the box down, get it settled and then stretch your hand over the cylinder and trigger starting from the top. Lay the top in place over you hand, slide the spring and guide into place and then SLOWLY slide your hand out of the box while moving your fingers over the top to hold the cylinder and spring firm. This leaves very little space for the trigger to slip.
V2 is easy. V3 triggers used to give me nightmares.
With practice, this gets pretty easy. Good Luck.