What bit to use a WP horse for penning?

I recently purchased an appendix mare who is very well trained in WP. I purchased her to retrain her to retrain her to event, but also to introduce myself to a more all-around type horse. To lighten the training, I take my horses cattle sorting on occasion. My concern is that my knowledge of WP is minimal to say the least, and I've always used snaffles to train and sort in. dg

I'm struggling right now to find her a bit we can agree on - the french link I usually use is not the winner, but considering we'll be spending the rest of the winter just playing around, I'm not really concerned about that yet. What I'd like to do is put her in something that I can sort in, but may be more "westerny" than the snaffle I usually use... I rode her in something with a shank when I bought her, and I'm thinking for this, I'd like to put her back in one. Any ideas on something that she might be accustomed to that would be acceptable to sort in?