Re: RG1570 Needing alot of Neck Shims
All guitars are different. Even with a 'perfect' fret level you're going to get some buzzing at some points on the neck depending on action and relief, and just the 'personality' of the guitar.
I consider 'standard' action for an RG to be this:
Relief at the 9th fret: about .3 MM, a little more or less depending on the neck and desired feel.
Action at the 24th fret, low E: about 2mm
Action at the 24th fret, high E: about 1.8 mm
Any lower expect some buzzing on any guitar.
With lower action you'll want to straighten the neck a bit... about .1 or .2 mm, but I wouldn't ever make a neck 'dead straight' no matter how low the desired action.
Nut height is a personal thing (within a certain range). Some prefer it a little higher, some as low as possible without it buzzing on the first fret when you play open. (ALWAYS adjust the nut AFTER setting neck relief).
A good rule of thumb that I use:
Press down right in front of the second fret (between frets 2 and 3) and check the clearance. You should just see a bit of space, enough for a few sheets of paper to fit. This gives you enough open clearance while being what most would consider low.
I usually go with a higher nut, I just like the feel better, but it's all dependent on taste and what you can get away with on the particular guitar you're setting up.