tee em,
On the NG, i believe the cabin altitude starts to increase from about 8000 feet pressure altitude, so at 10 000ft, you will have about 1000ft cabin altitude... definitively you should check the RATE of cabin altitude passing 10 000ft.
Pressurization maintains an average of 8000ft cabin altitude at cruise.
So maybe 2000ft cabin altitude/10000feet? I m jobless for the next month..so cant really check in the aircraft...
The cabin altitude versus pressure altitude can be found on the overhead of your aircraft (under the pressurization panel)and up to you to calculate your rule of thumb;-)
Ciao