I gather, but it's part guess, o-ring type/grade will have to do with tightness, a tighter fitting o-ring will likely leak less, but the catch is probably give more friction, it's also got to do with oil thinness your using as well.
This applies to all the shock parts, hence why you can get lower friction pistons, and even shafts, less friction means a better working shock, but really I try to build my shocks leak free so far, I don't really enjoy building shocks that often.
Big tip I know from some of the pros has always been some slime on the o-rings during the build, it's supposed to make them smoother and leak less I think, I'm using like synthetic brake grease on mine, super slippery and won't react with anything plastic or rubber.