As to the zero at 25-30yrds. umm. I've often heard people say that if you sight zero at 25 you will be about 1'' high at 100 and so forth. I believe that there are too many variables to do this, height of scope,MV, bullet BC, etc.
As in doing this you MAY be close at 25 and 100 where a 1/2'' won't be noticed, but as you extend your range the differance will be multiplied.
I have a ruger m77(lam/ss) in 270wsm. A great shooter with the 140Accubonds.
Just for referance, I'm at zero at 300yrds, 1 5/8 high at 100 and about 1'' at 200.
The only real way to find out what your setup is doing is to SHOOT IT.
good luck,DM