What gauge strings are recommended for Drop A# or Drop A tuning?

Thanks.

If you are playing lower tunings, use thicker strings (higher gauge)
You might have to adjust your bridge height though to avoid string buzz on the fretboard

What strings do you use in standard tuning? What scale length, and what guitar?

I last used a .068 for A# on a 25.5" scale, haven't tuned any lower on a standard scale guitar.

I went .071 with my 25.5" sevenstring, drop-A tuning.

You might wanna try a thin set first, as zodijackyl recommended.

as far as string guages go.. here is the rule:

higher (thicker) guage: bit harder to play, vastly better tone

thinner strings: easy to play, relatively poor tone