i would use the manufacturers recommended
lube for string and rails to avoid any warranty
issues.
you may want to try something else.
broadheads, . . .i couldn't say.
i use 125 grain heads because that's what
i like and shoot the best.
i've not had good luck with mechanicals,
so i use the magnus two-bladed heads
this is so much like fishing or shooting
guns, or finding a mate, or anything else.
you have to try and see what works good
for you.
and like anything else, you need to practice
and practice, and practice some more to
be able to make that necessary good clean
shot.
(and keep your fingers out of the path of the string)
good luck with it