Here are three ways to deprime:
Get an RCBS Berdan decapper.
Use the hydraulic method. Make a piston that just fits the neck, fill the case with water, smack the piston with a hammer. Primer needs to be over a hole. Effective, but messy.
In addition to the RCBS tool, I have: Drilled a hole in a piece of hardwood slightly larger than the case. Slit the wood to the hole. Drop a case into the hole, clamp the wood in a vise, to lock the case in place. Tap a slender sharp spike into the cap at an angle, lever the cap out.
Repriming is easy.
I wouldn't alter the cases with a central flash hole for Boxer primers. Decapping is no big deal. The pocket may not be sized to accept a Boxer primer.
Contact North Sylva in TO. They import RWS and may be able to supply the correct primers.