My first load is also one of the best. In high school in the '70's I killed everything from doves to deer with this load. (For the deer, I substituted some lead fishing sinkers, pinched closed. approximated #2 buck shot at ~.28" ircc).
I used most any hull, 16.0gr of Unique, and any 7/8oz or 1oz wad and enough shot to get a good tight crimp. I loaded these with a Lee loader and #109 powder dipper. (Actually throws ~15.8gr of Unique). I even shot my first 25 straight on a skeet range with this load through a borrowed Charles Daley o/u.
For early season dove's, nothing ever quite matched some extra hard #8.5's I was given. (a partial bag from widow of deceased trap shooter).
For general wing shooting, I liked #8's, but for late season dove's I found the 7.5's prefered. Squirrels/rabbits got #6's, but my favorite was a single bag of #5's I managed to run across. But, magnum #6's will do....... Even for late season dove's with 2-3/4" 1oz loads.... But, I also dropped many mallards with that load....
Nowdays, I've gravitated to 15.5gr of Universal for 7/8oz and #8's or 9's, and 17.4gr of LongShot for 1oz. with #7.5's. But I do have some 3" Bismuth factory loads for ducks/geese.
But, I'm shooting these through a fine s/s I don't want to abuse like I did my Mossberg M500 pump I had in highschool..... (I even used the 16.0gr of Unique and SP20 wad in 3" hulls w/1.25oz of shot..... and blew a few primers and case heads too!!!).