I just measured my Dewalt (a UK model of the 611).
The diameter of the lower portion where the boot will fit is 69 mm. The amount of space from the bottom of that (69mm) body to the bottom of the Inventables made holder for the router is 28 mm. We have had some discussion about the difference between the UK Dewalt models and the US one and that has centred around the mains lead. It is possible that the top plastic is different enough to cause the US model to protrude a different amount than mine (28 mm).
I see that this idea has been done before but it is always nice to have a new take on it.
Good luck with your design.
Peter