if you have this center finder (mine came from amazon) that has the holes in the arms and the hex head screw to hold the blade in place (I know, very nitch market) you may find this doodad helpful.

you can keep a hex wrench handy all the time and misplace it and wind up never knowing where it is, or, there is this thing.

the hex end fits the hex screw nicely with just the tiniest bit of sanding or filing, and the entire thing fits inside either of the holes in the arms with nothing sticking out. its a friction fit but its so light it holds nicely.

quick disclaimer, its plastic and 3d printed so its probably not a good idea to put too much force on it, but it does work to lightly tighten the hex screw. if I find issues with durability with it I will come back and update this.