Here the edge connector pins have been glued with 24 hour epoxy glue, together with a 1/2″ 2-56 bolt and are drying with the pins gently positioned into a female Roland 24 pin connector. I happened to have one spare, but you could use a synth’s connector for the alignment. This will compensate for the inaccuracy of the drilling. For the first couple of hours drying, I had set the connector 5mm distance from another piece of perspex, held apart by bolts to ensure the connector pins all extend to the correct depth. The 1/2″ bolt turned out to descend the correct depth due to the thickness of the perspex, otherwise I would have cut it down with the Dremel.