I think the best thing to do would be to search thingiverse for a band available in your area like “mpcnc dewalt” that will pop up any pre made mounts and give you an idea of what others are using. I can’t recommend things I haven;t tried but be careful not to get a really big router they are not needed and can be harder to use, get something that is in the size range of the 660. If all else fails the import spindles do work.
I decided to order one of these spindles: https://www.aliexpress.com/item/NEW-Spindle-the-CNC-Spindle-Motor-ER11-500W-52mm-mounting-bracket-spindle-clamp-for-PCB-engraving/32341330193.html?spm=a2g0s.9042311.0.0.PuRgy4
mcmasterp says: EDIT: there is a 52mm spindle holder on thingiverse that works great.
I tried to find it without luck. Could you provide a link to it?
Here’s my remix:
52mm toolmount mpcnc with line laser found on #Thingiverse https://www.thingiverse.com/thing:1083357