Enlarging Rail slots for Kodiak Base

What is the best method for enlarging Weaver rail slots so the Kodiak H1 mount fits. Can it be done with a file and if so, any special kind of file?
Thanks Scott

It can be done with a file. I prefer to use a safe edge file, only cuts on the parallel surfaces with the perpendicular surface being smooth. I removed material from each side of the slot slowly checking the fit frequently.

If you have a local machine shop, they could do it in 10 minutes.  Yes a file will do the job.  Just go slow and check to make sure you're not canting the slot.

I have enlarged rail slots with a file.  Masking tape will help keep the file off the bottom of the slot.  I have also added slots to a base to position the rings where I want them, again with a file.