I modified mine in much the same way, although the VQ has two rails obviously. I had a few issues...
As the fuel will be flowing through the one reg, if you have a pump failure, the other pump will try to take over and you wont know until you lean out on the next squirt. I would recommend running 2 non return valves if possible before the reg, just so one pump runs 3 injectors only. That way if one pump fails you will know about it.
I also had issues with the ethanol rated Proflow teflon fittings, the barbs on the olive were too short causing them to weep at pressure. So much for 2000psi. lol. The Ebay lines I changed to have been perfect as have the twin Walbro's intank.
Good luck with it.