I apologize for the long delay it took a while to get tooling and get the machines spun up alongside some other things but I finally have the first few prototypes cut and in hand.
As suggested, there is a 1/16" solid dowel pin at the rear of the sight and a 5-40 set screw in the front to retain the blade. It appears to work out very well - there is no play in the front sight at all and it is still quick to change out with minimal hassle. It should also eliminate the sight getting knocked out on barricades, holsters, etc.
I will share more pictures when the bases are bead blasted and installed in the barrel but for now at least there are two of the base itself below.