Giving to the bit

Question
I have a 6 year old Arab. I ride in hunter and I've had tons of problems with getting him to back off the bit at all! I've tried many different types of bits and nothing seems to work.
I ride with a martingale and use my legs to try to drive him into the bridle. If I put to much leg on him he gets really hot and sits down on his hind and lifts up tomuch in front. If i try riding without a martingale his head is all over.
I've tried givign him a small reward of releasing a little when he finally gives to me, but then his head goes straight in the air.
Right now I'm using a D-ring snaffle with small copper rollers on it.
I showed him in a pelham and he would set his head, but I felt like I was constantly hanging on to his mouth.
A kimberwick doesn't do anything either. What type of bit should I use? Is there any other way to get him to give in to me at all?
Thanks!
Stefanie

Answer
The  bit you are using is a very good one for this young horse.  If you can find an 18 wheeler inner tube, cut the inside circle all the way around and open it out.  Next cut 2" from the outside edge.  Cut all the way around the circle. Cut another one which will be a bit smaller.  Next, take one end of the strip and cut a verticle slit,3 inches from one edge.  (this is where you will be able to attach a bit ring).  Saddle or use a surcingle and attach these rubber "reins to the bit and the saddle.  First adjust them with minimum contact.  Work the horseon longe.  As he accepts the pressure, gradually shorten the reins and continue in this manner until your horse learns to give to the pressure of the rubber reins.  I  believe this exercise will be of benefit to solve your problem.  The rubber gives much quicker so the reward to give to the bit is an immediate response.  Have you checked this horse's teeth?  If not you need to do this as well.  I hope this will help with your current challenge.