Thanks for input. I shouldn't post in the heat of the moment. I'm just frustrated and discouraged, but it's alright. I'm down off the ledge and ready to go for a ride again. Shredded bar tape is just another chance to try something new, right?
Still bummed about my bibs, but it could be worse. Maybe some bad luck, maybe not, but I'm none the worse for wear.
I've been practicing cornering a lot. The physics of it makes sense as far as leaning/counter steering, and I've been working on picking and holding steady lines, working on my balance, working on apexing, working on countersteering/leaning etc. But I clearly need more practice at it, so that's what I'll do. Thinking about it more, it very well could've been the painted lane stripe on the bike path there, I slid right as I was apexing in a left-hand turn, and I may have touched that line while apexing. Or, I just plain messed up and I need to keep practicing. Or both.
Would a set of rollers really help me much with balance and handling? I can ride year-round in SoCal, I have no need for indoor training, but if rollers would help my balance and bike-handling more than riding outdoors then I'll get them.
As far as fitness, I'm certainly not where I need to be yet, but this wasn't from over-doing it. Today was a pretty leisurely ride, conversational pace with friends, just out for coffee. Easy ride, well-hydrated and nutrition well taken care of. My eyesight is very good, my balance off the bike is fine, I've had a physical recently, and the doctor congratulated me on my weightloss. This is the best shape I've been in for a long time. My blood pressure is down, my resting heart rate is way down. Cycling has made me much healthier...when I'm not hitting the pavement, at least.
As far as tires, I've ridden some Specialized tires in 700x25 previously, but I've just been using these 700x23 Michelins for a while so I could feel better about replacing them. I felt bad replacing brand-new tires that seemed perfectly fine for me. I've never experienced any grip problems before, very seldom get flats, and I find few complaints about them from others online. But my plan was to upgrade to some GP4000s 700x25 in the near future anyway, to see what that hype is all about. I've been hoping to upgrade my wheels some too (upgrade durability-wise, although in getting a strong set of hand-builts I'll probably end up with a weight upgrade as well), and was hoping to get the nicer rubber at the same time. Or whenever I saw them on sale at PBK again.