ooh my favorite answer for canter issues!
Trot trot and then trot some more. Then trot more. Trot hills, circles, patters, fig 8s. Trot again. Trot transitions walk trot walk trot. Then trot some more.
Better canter doesn't come from working more at the canter. Better canter comes from better trot. So even thought your trot is good, there's some muscling lacking for your horse to not be able to balance (you said he's a bit on the fore in the canter).
The best way to test this is at the trot, without changing directions, change posting diagonals randomly and see how your horse reacts. If he throws his head up, hitches his stride, or bobbles or his balance/rhythm/cadence changes at all, he's ot as fit and balanced at the trot as you may think. You also should be able to change directions without the horse losing his balance or popping his head up or off the contact.
In this case, I would NOT recommend a stronger bit, as I believe the horse may slow down but will likely lean more or learn to balance off the bit. Rather than you working to get stronger to hold your horse together (really, I want my horse to balance themselves! I will never be strong enough to hold up my horse!), i'd much prefer to see a horse learn to balance and work WITH the rider rather than one holding/supporting the other. This is not to say that there will never be a time when the rider needs to help and support the horse - this happens. But the idea and goal is to have the horse working towards self-carriage, regardless of discipline.
Try the trot exercises, and once your trot is solid even with changes of diagonal, changes of direction, and all sorts of figures and shapes without breaking gait or balance, then try the canter. At that point, trying two point can help to let your horse figure out his balance without you in the tack and i'd be willing to bet the canter comes much more easily!
My OTTB I had for OVER A YEAR before we ever cantered. We trotted for a year! And when we did canter, it was soft, supple, and balanced :)