Hello Nick,
I'm not sure that I would use the words "instead of" here, but not everyone is going to either feel comfortable or be able to do bodyweight pushups for more than one reason. Hand stand push-ups would obviously demand lots of strength from the participant and some balance also, even though a wall may be used to lean the feet on.
To answer your question Nick I would have to say yes, your MP would have to be equivalent to your BW. But on the flip side, the wall may take some weight off your BW as would happen if you were to (say) lean on something whilst standing on a scale weighing yourself. The best way to find out where you stand (no pun intended) is to actually try one push up.
To me it's easy but then I used to be a gymnast before I ever touched a weight. So lifting my own bodyweight since the age of 7 was something I became comfortable with.
Let me know how you go please. Thank you.
PS: Always make sure you are fully warmed up before attempting to lift your own bodyweight. So please do raise your body temperature, then get stuck into some stretching before attempting even one (normal) push-up!
Fadi.