First I would get him good in the bridle. A horse can learn to give to a bit if you use a little feel and time your release properly. I know you want to ride bridleless but your horse needs to learn to really respond to the bit. Get his teeth checked if you haven't already. Then you need to teach him to give to pressure. He should flex vertically and laterally. If you can't get that then you won't have any control without the bridle. In my opinion bitless bridles are garbage and are used by people that for whatever reason won't train thier horse properly. Use a snaffle bit and ask the horse to bend his neck in one direction using direct rein. Wait until there is slack in the rein and the horses feet are still. Don't pull very hard and as soon as the horse give then release. Repeat this on each side about 500 times. The better your release is timed the faster the horse will learn. After the horse flexes to the right and left then use both reins and ask for vertical flexion. Use the same feel and timing as you did with lateral flexion but this time use both reins and don't release until the horse breaks at the poll. This process will take several days if you work diligently at it. If you don't it will take forever. After your horse understands that he should be giving and moving away from pressure he is more likely to understand what the neck rope means and everything will go much easier.
When there are holes in a horses training it makes it hard to progress very far. Even though it may seem like it is unrelated everything we teach a horse is built on previous training. You never know where that hole is going to weaken the entire training structure.
I'm sure my comment about bitless bridle will cause some heartburn for someone but that's the way I see it. If you want to ride your horse bridleless then that's fine. It's an impressive trick and fun to do but to do it properly your horse needs to be very handy first.
There's nothing like the Rockies in the springtime... Nothing like the freedom in the air... And there ain't nothing better than draggin calves to the fire and there's nothing like the smell of burning hair. -Brenn Hill