I have the joy of owning an Ibanez IMG-2010 Guitar Synth, which can be had quite cheap on Ebay, yet are excellent quality Steinberger style guitars, and originally sold for quite a princely sum. Wayne Joness' very informative GR-300 site extolls the qualities of this beast in great detail. I'm yet to do the conversion to a DB-25 pin connector and fit the G-202 hex fuzz circuit, but it's planned.
With the cover slid down over the bent angle, the connector itself still stands proud, different from the original Roland connectors. However, this is fine for the male connectors since they adjoin the guitar synths, which won't be moved around, compared to the female connectors adjoining the guitars. For these cables, the other end connecting the guitars use DB-25 male connectors plugging into DB-25 females on the guitar.
After drilling the perspex base, even with a drill press, I was off in my alignment…grrr. This was a combination of using a broken 1/32" drill bit, inaccuracy of the Dremel drill press base and that I didn't centerpunch the marked drill holes accurately enough, nor checked the prospective drill hole position sufficiently. Other photos indicate that this level of inaccuracy didn't turn out to be a problem in practice. The edges of the perspex in this photo are pretty rough, due to cutting the perspex with a hacksaw by hand (no bandsaw available). After this photo, I flattened and straightened the edges with a hand file. Some of the edge connector pins and 1" 2-56 bolt for reference. I ended up using a 1/2" bolt as a centre pin.
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.