Kelly, you already know my stance on the issue; if you want, I can certainly pick one up for you at my discounted rate.
The one thing I will say is that you can get independent side action with a French Link as well - just not with a single joint.
Does Lizzy have any bits you can try in his mouth? Some horses respond better to different bits; for instance, Denny loves French links, and doesn't tolerate single-jointed bits well, he really fusses. Some horses prefer a roller. Some horses prefer a loose ring.
I definitely stand by my theory that a double jointed bit is the best type of mouthpiece for most horses.
OH!! And I have a 5" eggbutt french link if you want to try it and/or have it; it doesn't fit Denny, and chances are it won't fit a Friesian either.