First I made each of the wargs as strait wargs with full manes.
On each warg I then super glued a very small 20mm wide by 10mm deep rare earth magnet.
Doing this was a total pain in the backside. So in future I'll use a 30mm wide by 10mm round magnet. Not the 20mm magnets. That will give more surface area to manipulate the magnet.
I then glued another magnet to the base of the warg riders. Again, this was a total pain as the magnet kept flipping in the drop of superglue or attempting to stay stuck to the tweezers I was using.
As such, I ended up with rider magnets not fitting to warg magnets. Despite this I did end up with proper magnet poles for each warg and rider (i.e. + and - poles). Odd riders could still sit on the same polarity side up magnets (i.e. + to +) as they would attach to the side of the magnet on the warg where the opposite pole was. But this made for an off center seated arrangement for the rider. Fortunatelly there was one warg for each rider to attach too. But using the 20mm magnets was a real pain. So be warned.