it's a great powder for both rifles... the .308 with Winchester brass will like around 44.4 grains with 168 match bullets... and 44.6 grains with the 165's is a good target area. With LC cases, drop those charges by .4 grains (and work up, yes, as always)...
W748 burns about like 4064 and Varget, so you're going to get similar velocities with like amounts of those powders (self-appointed mall cops stand down, I did not say exchange data with these powders!
)...
Folks who use 748 in non-optimal charge weights report temperature sensitivity, but with the right charge amounts, it's not going to swing velocities in temp changes nearly as much as some would have you believe. Of course it's not as good as any extruded powder for temp stability--but again, not as bad as you sometimes hear reported, provided you've loaded right.
W748 meters like a dream, and seems relatively consistent lot-to-lot in my experience.
With 175's in the .308 using Winchester brass good performance should be found in the mid 43 grain range, likely around 43.5 grains... 43.1 grains for Lake City brass.
Dan