@ShaneBell Did you ever end up upgrading your dewalt 611 bearings?
I get about 24 hiurs from a set of brushes, although the wear goes up rapidly with higher RPM. At setting 3.5, brushes last for maybe 100 hours of operation. At setting 6, brushes last less than 24 hours.
I now keep a couple of sets of spare brushes handy, and inspect the brushes every few hours.
Now, I want to replace the bearings. Where can I find the right bearings, preferably higher precision than the originals?