Enquiry about balancing a diy brushless spindle

Hi,

I'm making up a little brushless spindle, ER20 holder, 10mm shaft, 24v supply and a 200KV brushless RC motor. I had the alu parts turned at work for the bearings and stator mount and now i've temporarily built it up just to see that it runs, which it did. Seeing it running made me wonder about balancing. Its purpose is to mill foamboard but the mill ends are long and obviously having it run true will help everything.

Is there a method to balance a motor once built up? Am I better to balance all the components and how would I do that?

Any suggestions or links most welcome.

Attachment 27683