Those magnets should do the trick.
The biggest problem I had was counter sinking the magnets themselves, as the Riptide is mainly hollow.
For the secondry weapons, I went magnet to magnet. The weapons and thier "docking stations" were easiest to drill, glue, then epoxy. For the big guns I attached two magnets to the arm and glued a steel plate to the bottom of the gun's compartment ( I dont know what to call it. The place the arm fits into!).
So far its working.