Drumgal, I feel a connection, a very positive one. I needed to "get out" of a County job back in 2006. I had 23 years in, but alas I was only 50. I looked at the numbers as "getting" 35% of full pension, while the naysayers on this thread would say I took a 65% hit. Still my calc was based on would it be enough to pay the bills? Yep. Obviously SS was not even a consideration for me then, someday it will be a nice raise.
I am also a musician, though not nearly as successful as you, and you are going to laugh, we just recently had to fire the drummer! But I bet I have more axes then you have sticks, lol, so I'm doing just fine. And that's what 11 years later now.
The key is if 100 percent with all the deductions paid the bills, including the mortage, why can't 75% with much less deductions, like not paying into retirement, FICA etc still pay the bills, leaving your PT job to fill in any gaps, and the gigs to pay for the broken drum sticks you throw to the crowd!
It sounds to me you are already In Like Flint, day one. Ditch the Boss. Pass Go. Collect your $200 and enjoy your well deserved retirement. I am. I so wish you would join our band...