I also have a Makita RT0700C router. I bought the DeWalt 611 mount with my X-carve.
In order to fit my Makita in the mount I ordered a cheap peace of Alu tubing. 80 mm high.
70 mm in diameter and a wall thickness of 1,5 mm. It cost me € 2,00.
I cut out a strip of 15 mm wide and fitted the tube inside the Dewalt 611 mount.
The Makita now fits like a glove.
An additional advantage is that it adds almost no extra weight to the DeWalt mount.
Hope this helps someone. Happy carving everybody !
Eric