I took the easy way out and booted from a DOS 6.22 floppy and set it that way :) I was using David_M's clock.com but that didn't seem to work correctly with GLaTICK though I didn't spend enough time to figure out whether it was a real problem or operator error.
Any way to patch PCDOS to address this issue? I have GLaTICK running on my Compaq Portable with an AST MegaPlus II (running PCDOS 2000 with a V20) and was scratching my head on why it didn't quite work!