Treso nipples will work on the big Dragoons and the Walker with the same good results as on the smaller revolvers. They are a different part number however. The Dragoons and Walker require a larger nipple. One of the areas they are different is length. They are significantly longer and larger in diameter. The cone part of the nipple is also longer.
The Possibles Shop lists both the Treso nipples for the smaller revolvers and the big Dragoons and Walkers.
I have a Third Model Dragoon with the correct Treso nipples. They also use Remington #10 caps.
So you can get Treso nipples for any Colt style cap gun.
Ransom Gaer