The thing about the CR is………at that high of an elevation, the CR is “effectively” less.
After you do a cranking pressure test and have a real number to look at.
Use the Wallace cranking pressure calculator to see how close it is.
Then change the baro pressure to something that represents being closer to sea level.
The cranking pressure number will go up.
Now, start lowering the CR until the cranking pressure number is pretty close to what you’re seeing from the test.
Whatever CR you used to come up with that result is basically what the effective CR is at your altitude.
Edit-
So I ran the numbers on Wallace…..
Current baro reading(station pressure) at Denver airport is 24.79”.
For a 446, 9.38cr, int closing point of 67abdc, and 24.79” shows 121psi gauge pressure.
At 29.50” it would be 144.
For the gauge to read 121 at 29.50” the CR has to drop down to about 8.25:1