To get back to the initial question (as I understand it..), can you be stable while above the vasi/papi.
I see no reason why not, as long as you determine that you will not have to make power/pitch/configuration changes to maintain the desired vertical path, and are able to maintain an appropriate minimum power setting.
It is the same situation as not having a visual vertical guidance, only steeper.
It is nowhere published that 3 degrees is the holy grail, It might be smart to use as you are familiar with the "picture".
As one of the earlier contributors mentions, when new on an airplane stick to basic/known situations, once you become familiar with an airplane you can give yourselves some more "slack".
GC