So, how low does the total timing have to be to keep it out of detonation?

For California 91 swill, I’d have built it with .040-.045 quench, about 9.75cr, and a cam that would put the dynamic Cr solidly under 8.0.

Which I’m sure would have broadened the tuning window with regards to the timing curve.

Edit...... plugging some numbers into the uem calculator....... it takes a cam a little longer than one might expect to get the numbers to work out.
For example, a 220@.050 cam intalled at 110, with 9.75cr has the DCR at 8.3.
Bumping the CR to 10.17 puts the DCR at over 8.6.

I haven’t tried pushing the envelope on that type of build....... when I hear “pump gas”...... I err on the conservative side.