While you have a hell of a lot more experience than I do in this game, we seem to be fairly similar in terms of statistics, yet there's quite a gap between us in this tank:
Some of that gap could be because I tend to run this tank in a platoon -- or it could be the gun -- but ultimately I guess it comes down to personal preference in terms of the gun and the resulting play style.
I do know one thing for sure, as soon as I went to the auto-loader my win rate and stats went way up, but YMMV.
p.s. thanks for the Podcasts and all you do for the community!
A big part of the difference is that I ran a ton of games in the A-20 as one of my first mediums when I was a nooblet. I have only recently pulled the tank out again to rehab it. My 90 day win rate is 72% mostly solo. Not as high as your WR in it - but you are a much better player than I am!
Interestingly - looking at 90 day stats my average damage is 890 or so while yours is in the mid 700s - so while I'm not claiming it's necessarily better, the "normal" gun is certainly competitive for my play style. A good part of the higher average damage is accuracy, with mine be 85% ish to your 70 ish. Difference is the automatic of course - but my damage per battle, kills per battle, and KD ratio are all competitive with yours in 90 days.
The good news is - pick the gun that works for your play style, because you can do well with either choice.
Thanks for the shout out about Tank Boom!