Stan;
In that situation, I would carry a 20 & probably l,oad it with 7/8 oz of #8's. If I were to carry a 28 I would only load it with 3/4 oz of 8's. I have never shot less than an oz from the 12 but would not hesitate to drop to 7/8 oz if it were a requirement.
Ted;
Your description fit me like a glove back in 1968. I was just finished with my apprenticeship, had a Wife, 3 children, one car & had turned that one car garage into another room. This one did shoot one deer, a doe. A state-managed area near me (where I worked at the time was on the property) had a Ladies only either sex hunt & my Wife carried it & killed a doe. This was also the area where I would occasionally go for the Fox Squirrels, though anywhere it was legal I normally shot a .22 LR with standard velocity loads. I did not like a sonic crack in a squirrel rifle so stayed away from the HiVel loads. Tried some shorts once but the rifle I was using, which was a tack driver with LR's threw a pattern rather than a group with shorts.
A year or so prior I killed my first deer, a 6-pointer that field dressed 174 lbs up in the mountains outside of Crossville TN. Used a re-worked Spanish
1916 in 7x57. It had already been modified when I got it so no chance of it ever being a collector so I dressed it up a bit better than it was. It had a bit of excess headspace so I reformed brass to fit out of 06 brass & loaded 140 Sierra bullets. The only deer we had back then around home was on that managed area. Now we have more deer than rabbits.
