I've been using XTol 1:1 with home made rotary tubes for the last couple of years in developing TMY and Tri-X sheet film. I did my own sensitometry guided by "Beyond The Zone System." I found that the recommended times from Kodak were way off.(posted 8327 days ago)It wasn't until about six months ago, and after I had done some serious printing, that I started experimenting with longer times and found that my sensitometry could use some tweaking. Bottom line - I generally multiply Kodak's recommended times by a factor of 2.5 to 3 in order get a good full-scale negative. For a subject with a "normal" subject brightness range of 7 (@ ISO 320), I'll be spinning those tubes for 18:00. Makes the wrists a bit sore, but the results are worth it.
I'd suggest trying much longer times at 1:1, or go to 100% XTol for the times you've been using.
Good luck.