I would suggest trying D76 or Dektol for this emulsion. IDK which would be better, but I think that one of them would be better than XTOL.
In my post above, there is an error. I should have said that commercial Glyoxal is 40% and I dilute it to 10% which is thus 4% Glyoxal.
And, NO, chrome alum is not known as a fogging agent. However, heat is. Maybe keeping the emulsion melted a long time under a safelight did the trick.
A prehardener is used before the developer. I use either formalin or chrome alum.
Water 800 ml
Sodium Sulfate 50 - 100 g
Formalin 10 ml
water to 1 L
pH 10.0 or same as developer
Preharden 1 - 3'
wash 2 - 5'
Run regular process cycle!