First of all, an SX610 isn't going to cost you an arm and a leg. Some morons price them like that, but such is not indicative of the norm. I have two here that I bought for $10, and they will go cheap on eBay when someone puts one up for a reasonable starting bid. They work just as well as a Suntour, and they could be confused for one at a distance:



It looks like an SLJ, but it's not; hence the cheaper price.

I understand what you mean now - the Suntour's top bolt is deeper than the hanger itself; it's threading through and contacting the Simplex hanger behind it. I'd take a file to the Suntour's top bolt. Easy fix, 5 minutes, max.

That said, threading aside, your VGT will never sit properly on the Simplex hanger without filing to the back. I assume that you want to reverse the B-adjustment screw (not any other screw - I don't know which one you were referring to) to clear the back of the hanger. If so, there's a flaw in your quick-fix: Removing the B-screw will only allow the RD to pivot without limit on the hanger, allowing the lower derailer body to rotate upwards into the chainstay and dent it, amongst other potential oddities.

That said, if you can't bear the idea of filing your Suntour's mounting bolt, you should feel the same way about modifying your frame. If you're so intent on the Suntour, why don't you trade your frame (or sell it off) and get something more suitable instead?

-Kurt