Designing and printing a part held in place by friction  

Designing and printing a part held in place by friction

I'm using PrusaSlicer and an i3 MKS3+ for this work.

 I need a part to act as a temporary clamp to hold something in place. The intent is for these parts to be held in place for just a few minutes, until the stronger fasteners can be put in place. (The stronger fasteners will either be toggle bolts or M4 screws and heat set inserts.) I have a wall plate with a front plate to go in the room and a back plate to go on the other side of the drywall. Here's a rough diagram:

It looks more complex than it is because I added a lot of labels to make sure everything is clear. This is a top view. The orange part is the front wall plate and it has a tube that goes back into the wall. The purple is the back wall plate that will be on the back side of the drywall. I'll be fastening the plates with something else, so the final fastening method is not important to this particular discussion.

Here's a view from the back, a cutaway view from the back:

The back plate would fit into the side of the tube that goes through the wall. The idea is it would slide into the opening shown here. I'm wondering if, when I slide the purple part into the slot made for it in the orange part, if I can reliably count on something like friction to hold the back plate in place until I can fasten it with something more secure. My concern is that counting on friction is dodgy. If I have to print the part on my Ender 3 Pro, instead of my Prusa, then I can't count on the same tolerances without making adjustments.

Side note: I'm using these wall plates in different places, and that includes different drywall thicknesses, otherwise I could just use some kind of pin to slip in place, but since wall thicknesses vary over a small range, I can't do that. The drywall could be from 1/4" to even 3/4" thick, and increments between one thickness and another are small, about 1/8".

My first thought on temporarily holding this back plate in position is, as I mention, using friction between it and the front wall plate, but I don't think that's dependable. Considering that I'm working with various wall thicknesses, and don't want to have to change the design for each location, are there other possibilities for holding this back plate in place for a short while? It does not have to handle more stress than the weight of the printed wall plates.