This or That? Bitting Addition

So I'm working with a horse to get her in a softer bit. Last time I did this, she really hauled her head forward and down (I had to stop because I couldn't continue working with her on that and it's been quite so time so I'm not sure how bad she'll be this time around.).

But here's my question. Which option would you use?

A.) Dee ring with slight twist in the mouth so it has the extra edge to it?

Or

B.) loose ring single joint mouthpiece with augrian metal so that the ring will slide and she can't pull on the bit?

Since you feel the need to ask, I will say use the loose ring.

A 'harsh' bit such as a twist, should only be used by someone who knows exactly what they are doing and why. I don't want to sound mean or anything, but if you need to ask here, then that tells me you are not sure that you should use it, and in my humble opinion, that generally means you shouldn't. Again, please don't take this as a criticism of your abilities or anything like that, it is just my opinion on bit use, not your skill.

I second the loose ring. If there's any sort of retraining going on (back to basics), or you're looking for a "softer bit", a simple snaffle is the way to go. Even a slow twist can be pretty harsh, and in my (humble) opinion over-bitting isn't the way to fix a problem. The mildest one would be my choice :)

What bit is she in currently that you are trying to work down from? Is she ina harsher bit because she grabs the bit and takes off? Does she simply not listen to it? Does she usually slam her head down to get the reins from you?

She's currently in a Kimberwicke. I tried her in the same dee before and an eggbutt, but I at the time wasn't able to work with her enough to really pursue change. It feels to be like she may be trying to grab the bit in her teeth (which is why I'm going to use a flash in the beginning) and will speed up, and that's why others have mentioned to me that a loose ring worked for them.

My suggestion (if you can get past the bit grabbing) would be to lunge her in the bit with side reins if you know how. Let her have it in her mouth for a bit before you ride. Are these the only 3 bits that you have access to right now?
I imagine that if you go straight from the kimberwicke that has some curb action and a chain, right to a loose ring snaffle your probably going to feel as if you have no breaks at all. So if you do go straight to the loose ring I would suggest starting super slow, maybe lunge her with her bridle on 1 day, next day ride her in it but only at the walk(lots of transitions, circles) ect ect ect
Im personally a fan of the slow twist dee rings. It worked wonders for me to get my pony onto a rubber bit. But in the end its all about what you and your horse are comfortable with.

I do have access to other bits (if you have any other recommendations) but those were just what people suggested originally. Thanks for all the help! :)