The gag/hackamore combos. I always read that they are horrible but I've used one on my gelding for the longest time and he's never seemed to have a problem.
Before I got him he was ridden by kids that were always in his mouth and his mouth is not as sensitive as it could be.. I kind of like how the gag part can give him time to do what I asked and gives plenty of warning to him, while the hackamore part helps refine what I asked since his nose is still Nice and sensitive. Usually I can ride him on a loose rein and use my seat/legs to tell him what to do.
I can ride him in a Snaffle also but I have to use more pressure than I like.. Where in the combo I can use very little pressure and with that it seems it's been helping make his mouth softer and he's even becoming more soft and responsive in a Snaffle compared to where he was before I started using the combo.
I try him in the Snaffle every once in a while. It will the Nice the day I can ride him in one and he be as responsive as he is in the combo I've been using.