Amp stand for Class A Hybrid and clearance.

My question has to do both with an appropriate amp stand and ventilation clearance for my amp. 

I have a Pathos Heritage MKii Class A hybrid weighing in at approx 200 lbs. it currently sits on my oak floor partially underneath my rack. (At 26” depth it sticks out a bit.).

The amp is 9” high. The space in which it sits is 14” high giving 5” top clearance. The rack space open L/R/F/B as you can hopefully see from the attached pic. 

My question is this:
What is the minimum top side clearance if I add an amp stand? I’m hesitant to use anything 3” high, which most seem to be at minimum. It doesn’t seem to generate a lot of heat, but I want to err on the side of caution. 

Unfortunately there are no alternative placements for the amp.

Thanks for any advice.

Not seeing how to attach pics