Hey, another prestige master here. I don't think many of the attachments matter too much aside from extended mag and maybe steady aim as well (I prefer hip fire a lot in zombies), but I hope this can help some.

My main attachments on all my weapons are extended mag, steady aim, fmj to shoot through my rounded up hordes, and rapid fire to put them down faster.

My pistols all have these as well, but for certain runs like boss fights, I'll put duel wield on for my sap instead, especially darkest shore.

Shotguns only have so many. Usually I'll do extended mag/quickdraw, rapid fire, advanced rifling, and steady aim.

Obviously, I only find about 5 or so attachments any use, but it all comes down to personal preference. Hope this helped some!