"(505) seems to be .1-.3 grains off at the higher weight charges
Perhaps, but I have no clue what you mean "at higher weight charges"; how high is that? And what makes you think it "seems" to be off at all?
IF you just want a new scale, go for it; either of your choices will be fine. The 1010 has a higher capacity but it's rarely used above the basic range. The Redding has a much heavier body for better stability. The only leveler a beam scale needs is the "zero" balance adjustment screw. No one has made a powder scale without magnetic damping for at least 50 years so that's no issue.
Anyway, reloaders really don't need extreme scale accuracy, if the accuracy is reasonable it's good enough, and your's is. It hardly matters if your properly developed 'higher charge' is 76.4 gr. or 76.7 gr., what you need is extremely precise repeatability. So long as you can precisely duplicate a charge tomorrow or ten years from now you have all you need for precision reloading; I'd bet if you keep your present 505 scale properly cleaned and the pivots undamaged it will do exactly that.
I'll note that I read a lot of people saying they use a beam scale to confirm their digital but I never heard of anyone doing the reverse; there's a message in that.