In a similar way, I generally use standoffs fastened into a backing board, then mount all the Pis, Arduinos, sensors, controllers, etc onto the standoffs. Using standoffs prevents any pressure on the bottom of the boards. Although this is not a problem when the underside is just solder joints (unless you use a conducting backing board), it can be an issue for underside components side as the Pi SD card holder.
The only problem is the cost of the standoffs. Nylon ones are not too bad, but metal ones are a silly price.
Some boards will take M3 fastenings, but M2.5 or even M2 may be necessary for smaller ones.