These saddles are adjustable height and carriers for length , threads don't strip, saddles are steel, carriers decent pot metal that lock in with setscrew into channel wall . Walls of channels are about 6.5mm wide, saddles about 12.
You could even drill and thread the saddles for a screw and spring and toss the carriers.
Cheap individual string bridges also use these exact carriers and saddles and cost about $4 US each in sets on the bay. The bridge shown is used on Lace Helix basses. I got this one from Grizzly a few years back. You can remove a lot of metal from the saddle assembly without it failing.
In a slightly different vein: Anybody got a picture of Bicentennial Tbird saddles? It seems those would be pretty easy to fab. I see a lot of mention about them being scarce. I never liked them, had a brass nut on mine and briefly tried to find some metal saddles... eventually got tired of the neck dive and thin neck and traded it straight for a '76 Stingray. Still wondering why I did that.