Buckshot.
When I patterned my 11-87 one day with different loads, I got a great feeling for recoil, pattern density, and range with the several loads. To me, that's the ONLY way to choose.
For 12 gauge, I'm happy with #1 or #4, depending on the layout of the house, distance to neighbors, etc. If ranges may be somewhat longer, and overpenetration isn't an issue, 0, 00, or even 000 might be in order, but I think of them primarily for hunting. (Legal here in LA for deer.) Recoil is more severe and pattern too tight for my taste on potential indoor shots under 50 feet or so.
I use a 20 gauge now. It has #2 or #3, I forget which is in the 2 3/4" shells I use. The 3" shells have the other size, but I find I stroke the action far quicker, smoother, and more reliably with the 2 3/4". Also, the thump of a 3" shell in a lightweight 20 ga. is not what I want to deal with in a crisis, whereas follow-up shots with 2 3/4" are far easier.
So, IMO you should forget birdshot (unless in an apartment) and see which buckshot feels best & patterns like you want, in your gun.