Like Brian stated, the general idea is to maximize end points and minimize linkage.

Maybe you can't change the resolution of the servo, but you can change the output 'gain' (servo output relative to stick input). If the servo originally moves 100% to get 15mm but then you increase end points and reduce linkage so 120% gives you 15mm, you have lower gain which emulates increased resolution. Maybe this is increasing system resolution, but not necessarily servo resolution.

I guess that was already said too, now that I read through this post again

I think what most people do is maximize the End Point Adjustment, and set the linkage so 100% travel gets you the just enough deflection for a contest flight, and use Dual Rates as necessary for lower rates.