The way you worded your reply, you may have thought I was talking about cleaning up after but the most important thing is cleaning up before.
So now you have some new shorts and it will be interesting to see if they make a difference. I can't help but think in reading your reply that you have a bike position problem when you're in the drops or even on the hoods. I assume you're down pretty low when doing a TT. Maybe you sit while climbing and you're using too high a gear? As for the ride with your mom, that would generally poke a hole in my theory or maybe mom is hell on wheels and it reinforces it. Is there someone in your area that does bike fitting? There is (unfortunately) no test or certification to say you're qualified to do a bike fit and there's a lot of self-proclaimed experts out there but to have a 3rd party go for a ride with you and look at what your position is might be useful.
I'll add one other thing. I had some seat problems some years ago and I went back to the guy who built my bike for advice. He's one of the most respected frame builders in the country and recently passed 5000 frames over 40 years and I take his word as gospel on all things bike related. He said when it comes to seat comfort, shape is 90% & padding is 10%, that when I found a seat the right shape for my anatomy I would be set. I am not familiar with the Romin, Regal or the Specialized saddles you've used and how their shape compares to the Brooks that you killed or the Sella (thats a lot of seats) but you may keep that advice in mind if you go out shopping for another seat.