Trust me….. I ran the gauntlet on self centering drill jigs. I have two of those similar to yours Max… but what I found was ……that if you could keep the jig in the same position and just slide it down the riser and drill both ends it work somewhat well.
But if you flip those 180 degrees, you’ll find out how far off center really is…. Drove me nuts!
Of course I was building bows with a second set of limbs, and wanted something consistent enough to build more limbs for other bows that I built in the future. That makes things a wee bit more difficult.
Same thing with using limb bolts as one location pin. Between tap drift and plus or minus tolerances on the threaded inserts themselves, those limb tips can end up 1/2” out of alignment when you mount them pretty easily.
But…. If you insist on using a limb bolt and single location pin. The simplest way to insure those limbs are on the riser straight is to mount them with the limb bolt only, straighten the limbs up, then drill though the limbs from the top into the riser.
Of course you need a limb butt overlay. But it’s a fool proof method I’ve used myself a few times years ago before buying my vertical milling machine. As long as you don’t need a second set of limbs built you are fine… if you miss your draw weight and have to go again, ya gotta pull the pin…
You know the funny thing is…. Even with the precise nature of using a mill with a machinist table using two location pins and an over sized hole for the limb that fit first time , every time. I still get limbs that mount up out of alignment a wee bit now and then…
It’s always something….
Kirk