let's look at it this way. when you use stock size push rods everything fits fine, in other words the 5/16" diameter doesn't hit the heads intake port. now when we step up our program and go to a 3/8" push rod it will hit the the intake port and will need a tad of grinding to clear the head. now if you go to a 7/16" rod you'll have to grind even more out to the point of braking into the port, not real good in any ones book. so to avoid all this lets say we install .400" offset intake rockers. we won't have to grind anything at all because the offset rocker moved the push rod away from the intake port and we're good. so they will work just fine on your heads, any stock head for the matter. did the pushrod angle change, you bet is did, a few degrees for sure. also the pushrod just got shorter by a thousandth of and inch. who really cares, some one building a superstock motor, you bet he does but us i don't think so. the shorter pushrod can be built longer which we all do when we build our motors to get the correct pushrod geometry. the angle you will need to move the lifter over to correct it. that's a tad more dollares then we are willing to shell out. it will also require a different cam lobe placement etc.etc. so in essence just go ahead and use them they will work just fine. you aren't building a swiss watch here.
also if you never want to destoy the pushrod angle you'll never get passed a stock head with stock parts.
i hope this clears it up for you and answered your question.