Hi Michael
I replaced my Novag Citrine pieces by very gently removing the original Novag magnets and fixing them into the base of my new pieces that I had drilled a recess into to accommodate the magnets.
You can see my new pieces on my web site on two boards. The first is called the 'Le Grande Citrine Arena' and the second is the 'Le Grande Citrine Deluxe'.
http://bryanwhitbycomputerchess.yolasite.com/
Regards
Bryan