IMHO asking bullet weights for a 30-30 is akin to asking what octane fuel to put in a 4cyl engine. The differences (however small) wont be noticable in most cases. Sectional Density is likewise a moot piont with a "tutty tutty". The velocities and ranges concerned arent enough to merit their consideration.

Personally I would opt for the 170 simply because of the slightly deeper penetration its heavier weight would allow (at least in theory). I havent seen the exception yet, but if for some reason your gun printed 150s MUCH better than it did 170s I would then use the 150s.

Using a tirty tirty for "all around use" like varmints, target shooting and big game hunting is akin to using a 1 ton pickup for daily commutes, drag racing and road courses on the weekends!!!

There are MUCH better alternatives out there for such jobs.
RA