If you are measuring to the saddles with them in the half-way position, then you can move the bridge back a bit. I'd move the top B/E saddle to about 3mm of thread showing and measure back to that. The other saddles will be further back than that when intonated, so don't worry about those. I'm not saying that you won't have to do any routing, but you shouldn't have to do so much, so a Dremel should be sufficient. Also, I'd stick with the 648mm scale length the kit is supposed to have. That will give you another 2mm of movement back (and you'd have 3mm of thread spare to move the top B/R saddle forward if necessary. That should get the bridge pickup cut-out pretty much over the hole. I know that these routs are pretty tight, so you may have to do a little work to get the bridge pup sitting well and moving freely, but a sander drum on the Dremel is all you should need.