There are a lot of factors that go into ideal comb height (personal preference, shooting position, how you mount the rifle to your shoulder, the structure of your face, is LOP correct already, etc.) That said, close your eyes, mount the rifle (offhand or in the prone), and then open your eyes...if you see black vignetting in the bottom of the scope (or worse yet, you're looking under the scope) then you could do with some more comb height (or lower rings).
A lot of people just lift their head ever so slightly until their eye is centered in the scope. Not a big deal at shorter distances, but it's inconsistent and gets problematic at longer ranges. I like a lot of comb, I really smash my face down on the rifle which puts it in the same position every time. My preference for this probably comes from years of shotgun shooting where fit is everything because you're "pointing" not "aiming." But it's all about consistency and repeatability in how you mount, which also applies to rifles.
There are lots of options. Check out Triad stock packs, Victor/Titan risers, or Cheek-Eez pads for starters. I know you said you didn't want to drill holes in the stock, but holes can be filled and painted over (unless we're talking about grandad's turkish walnut). If a stock doesn't fit, it's not doing its job so modify it or replace it, but that's just my opinion.
On a related note, is your length of pull already where you need it? Do that first because it affects where your cheek sits on the comb, and consequently how much comb height you need. If you're 5'8" 160 pounds then the factory LOP is probably fine (assuming it's 13.25-13.75"), but if you're significantly bigger or smaller, you might need to address LOP. It's amazing what a difference half an inch makes.
Blah, blah, blah...I'm done.