I'm shooting TXP 320 that went belly up in 1994 and 1996 and finding it fogged but useable. Plus X from the same era looks fresh. Neither was stored well after about 2007 but they both had spent years in a freezer before that. HC110 does help, especially when used at 65 degrees instead of 68. I started at 8 minutes with a 1:49 mix (Jason Brunner's simple set-up) and didn't change the timing for the temperature, but you may want to lengthen it a bit. YRMV.
This is, of course, if you want to change anything about what you're already doing. No sure, since your images look great.