So, I have a mare that was started by an OLD school cutter. She moves beautifully and is super soft. Was started on a flag but never put on live cattle. Previous owner took her home and turned her out and occasionally brought her in the use at sorting practices, etc. All previous owner has ridden her in is a shanked snaffle (essentially a pretty Tom Thumb, in my opinion) and a training fork. I will obviously be starting her on the pattern and am at a bit (haha) of a loss as to what to move her to or to just not fix what isn’t broke. She’s super light and flexible in the setup she’s used to, I just feel like she/I will need something slightly more forgiving for barrels. Thank you! 

I'm not by any stretch, a bit expert. But if she were mine, I'd probably try a plain o ring at first and see if she stays light and responsive, then move around from there if needed. I personally like to try to use something very simple if I can get away with it. For instance,  we just got a horse, we tried him in the sellers set up... a walt Woodard twisted wire with a port and long shank, a rope nose band tie down... (roping horse) he worked beautifully, very light and responsive... we got him home and I just put an easy chain bit with medium shank and a regular tie down when we roped monday. He was a tad pushy thru it, not bad, but you could tell he didnt have the same respect. We moved him into a ported bit with medium shank and he worked better. For at home conditioning,  I have her ride him in a plain o ring snaffle and no tie down. I like to have an arsenal of bits and set ups in my trailer! (May or may not have a slight addiction)