With regard to bell boots: I think no matter which brand you purchase, if the horse is over-reaching regularly when its ding-batting about, then they will get ripped and pulled off. So probably best to just be prepared to replace them frequently.
These are the ones I ordinarily use for unbalanced youngsters:
http://www.loxleyequestrian.co.uk/displayFullBaseItem.php?baseItemID=23
I've never yet seen a bell boot that will protect a horse's sole from forging.
But then this presumes that over there over-reaching and forging are the same as here:
Over-reaching: when the horse strikes the coronary band or heels of a front limb with the toe of a hind limb. This can happen because of deep going or when a horse is unbalanced but be reassured that its not at all uncommon to find young horses going through "stages" of over reaching as they are growing and developing.
Forging: when the hind limb strikes into the sole of the foot of the forelimb and similar cause: when the horse is tired or unbalanced or because the hind feet are too long