Help determining what I have in the way of tilt.

CameraTilt_ASTAP_FLT91_ASI294MCPro
CameraTilt_ASTAP_FLT91_ASI294MCPro
Did you try to analyse with NINA Hocus Focus plugin to verify the ASTAP measurement? (if not, you should ...)
I recommend this thread on CN:
https://www.cloudynights.com/topic/809050-tilt-discussion-astap/
It has all you need to know about tilt.
CS, John
P.S.: Yes, 300s is far too long. Try 30s or less with L filter.