Train Partial Panel w/ Dual G5s and 750 GPS?

The airplane is a 172 with dual G5s, a GTN 750, and GFC 500 autopilot.

Back in the days of yore you could simply cover the attitude indicator and force an instrument student to use the rest of the instruments.

Is simply covering the upper G5 enough? But then what if the student wants to change the HSI and an AI...?

Am I missing something? Trying to make this harder than it needs to be? What have you seen DPEs do?

Thanks! It's my first instrument student, and I want to do it right/cost effectively.

Edit to add - thanks for the useful information/tips!