Bitting question

["guest@endurance.net" <guest@endurance.net>]

A. Perez AmandaPerez@ureach.com
 I have, I think, finally found my 'dream horse' after months
of searching.  I hope to be bringing him home for a two-week trial period in a couple of weeks. He's 16 hh TWH, big and brawny (a bit bulky for endurance, but when and if we ever compete it will just be to complete) and highly sprited... this horse wants to GO!  Very responsive to legs and seat.
He acts like he's going to 'blow up' (prancing, head-tossing) but never does - always stops when asked (I even had the owner ride towards the barn on another horse: I held him back until he got ansty, let him go into a gallop, stopped him half way back to the barn and the other horse: stopped on a dime.  Turned and rode away from them: no explosion! tried every thing I could to get him to 'lose it' but he never blew)

He is extremely sensitive to the bit - you HAVE to stay out of his mouth: if you keep contact ont he bit he tosses his head and fusses (nothing unmanageable), but does stop.  He was in a Tom Thumb snaffle (jointed snaffle with very short shanks) which was a bit narrow for him, and he kept grabbing one shank in his teeth on one side of his mouth.  I'd like to quiet his head down - lessen the tossing and fussing at the bit.  I'd also like to be able to ride with more contact then he's happy with now to get him engaged and on the bit.  Here are the options I've been considering (in addition to getting his teeth checked)

1.  A hackamore or bitless bridle (any brand recommendations?)
2.  a hollow-mouth eggbut snaffle
3.  a kimberwicke
4.  a rubber straight-mouth snaffle.

Comments/suggestions/alternatives?