I followed this guy's advice (from
this site):
Even though, for SG flat tops, they only come in short, non-angled, you can still use the tall angled version made for arch-top. It may not fit perfectly against the SG's flat top, but it still fits fine. There is just a little space under the center of the ring, which doesn't negatively affect anything, and you can't even see it.
However, if you want a perfect fit, it is very easy to take the tall, angled TS for arched top guitars and make the bottom flat to fit SG type guitars. Just hold some 150 grit sandpaper tightly on a flat suface (tabletop, workbench, etc) and rub the TS back and forth until the bottom is flat. Finish up with some 220 or 360 grit and you're done. Quick (about 2 minutes max), easy, NO additional cost or time waiting for Duncan to start manufacturing the correct ring.
Bad mistake. He might have been lucky. One slip-up with the cable under the triple shot touching the sandpaper and I destroyed the bridge triple shot. Only $70 down the drain!! These things are very flimsy. Don't do this, even if you read that it's easy! You can hardly see the damage in the next photo but believe me it's there. Note the bit of red missing on the ribbon.

I'll now have to find a plain black pickup ring and use that, and only have a triple shot in the neck position (which is where I really needed it, anyway). I also wouldn't recommend the triple shot in the bridge position because the switches sit very high and get in the way of your pick and hand.
On a more positive note, the TonePros bridge and tailpiece set and the chrome locking Grover tuners arrived today. I installed the latter and then replaced the stock Epi bridge and tailpiece, and added the Dunlop Heavy Core strings to test them out. Not sure if its the strings or the overall setup but nothing sounds right at the moment. I'm just doing it for testing purposes at the moment and the guitar will soon go to the tech for the rest of the mods but I'm hoping I'll get it sounding at least as good as it did before the mods soon with some height tweaks. On the positive side the volume bypass does make the guitar noticeably brighter when engaged, so that's working
It might be the case that I need better grounding for the shielding but I suspect the strings are a big part of the problem, and possibly the fact that the bridge has not been properly set up for the bigger strings. I think I will switch to another set before taking it in for setup. I don't like that heavy unwound G.
Here are some more photos:


