I shall get a "family photo" of the heavy 12, 10, and 8 up in the next couple of days.

As to a 4 bore: it would certainly round out the "family", though I would not really have a huge urge to have a 4 bore with the intent to do much recreational shooting.

Years ago I got to shoot a Bland single 4 bore owned by Ray Meyer (I heard that it went to Alaska after Ray's passing)…….I felt it actually was not that much more "invigorating" than an 8 bore to shoot from a standing position on my own two hind legs.
Just that a proper 4 bore weighs about like a truck axle…….tho much better looking.
- Mike