I've never found much difference in accuracy with handgun loads. Of course, most of my loading is for a Glock and a subcompact at that and I'm not a super-star pistol shooter.
"Working up" handgun loads for my purposes is only for confirming that I'm not over-pressure. I usually load 3-5 at each level.
Rifle loads, well....
Maybe I'm just lucky.
I see all these reports of load work ups where one load is shooting 2 inches and another is shooting 1 1/4 and they finally find one that shoots maybe 3/4 or 1 inch....
My own loads, I struggle to see the difference from one to the next. Different powders, different bullets.... they're all about the same. If I my gun seems to shoot around 1/2 inch, it just seems to shoot about there. Maybe 3/4 sometimes but I never see 1 1/2" groups. Factory ammo, reloads, heck, even Trail Boss "mouse fart" loads. There's hardly any difference.
For charge increments, I use Dan Newberry's
suggestion of .7-1% of expected max charge. I've always intended to use his load development technique, but I haven't had the need so far.
Load work ups have always been pretty uneventful for me. I've never seen surprising good or bad accuracy at any point (or particularly different even) and I've always reached published max loads with no problems.