A .675" choke might be fine for shooting the smaller size buckshot, but will almost certainly cause bore damage if a slug is fired through it.
I'm looking for something that will pull double duty shooting either slugs and/or buckshot. It doesn't necessarily need to be the best for either projectile, just something that will be a capable survival weapon/ zombie slayer
I did some shooting with some flush fitting Imp, Mod and Full chokes and found my Modified choke patterned the best with my handloaded #1 Buckshot loads and shot slugs quite well.
I might just pick up an extended Modified choke and leave that in the gun outside of the Turkey hunting season.