For those of you that use baitcasters to throw hard jerkbaits and weightless senkos, what size line do you use?  I use the same rod for both of these applications.  I have always used 12lb Floro (Sunline Sniper), but thinking of going to 10.

10 and 12 pound test are perfect for that application. 

10 and 12 pound test are perfect for that application. 

x2

I use 12, I would use 10 if I didn't have fish with teeth around

You gotta consider what your throwing in to, I like 14 or 15lb test when I'm fishing around the trees and grass out here... (For Senkos)

I use 12 for both as well. I wouldn't be against using 10 either. I think you're good either way. 

Hard jerks baits, as in pointers, I use #8

Senkos, #6 all the way to #20 depending on size, rigging method & cover type as well as having a general understanding of the ( bass ) size potential of the water I'm fishing..Cover probably trumps all other considerations, ultimately

8-10 for jerks, and senkos if you use drag. If you are a "tighten it down and rip em out" type of guy then you probably want 14/15 for senkos.

I get better hooksets with 12# I found 10# had too much stretch.

I fish a great deal of thick grass and stumps in Toledo Bend so I go with a little bigger line. I use 12# for Jerkbaits and I use 15# to 17# on Senko's. If I was forced to use the same line for both I would try to settle on maybe 12# to 14# if the 14# would work the jerkbait the way I wanted. The other guys have given you very good info.