When the saddler came out the other month to tweak the panels on my Mayhew and on my off-side Beck, we did a little experiment where we only attached the balance girth loosely and only used the first two buckles on my three buckle girth. My saddler said that both trees on each saddle were a good fit for her, but wanted to see if it was the full balance girth used on Hattie's BIG barrel that was bumping my saddles forward and if the third buckle on my three buckle girth, was causing extra drag on the saddle as well since the third billet is set far back on both side saddles.
Well, lo and behold, the saddles stayed put with a loose balance girth and the only the first two billets used on both saddles. I didn't even need to use my gel grip pads.
Unfortunately, I can't show with a balance girth flapping around and all I had wide 3 buckle girths so my saddler suggested that I get a narrower 3" wide girth (my ones are 4" wide) made from soft leather so it curls back away from her shoulder due to her forward girth groove and get it made with a short attached balance girth. So I had a tack room clear out and sold a few of my regular side saddle girths and invested in two side saddle combi-girths, a near side and a off-side model from Northumbria Equine.
Because a regular balance girth attaches to the front of the saddle and then goes around the horse's widest point of the barrel, Hattie's big barrel was bumping the balance girth, which in turn, was buckled onto the tree point of the saddle, causing it to move forward. With the short attached balance girth, it only rests on the rests on the side of her barrel and there are things buckled onto the tree points of the saddle which means, less things to drag the saddle forward.
I really like these combi girths and any side saddler can make them or adapt an existing normal side saddle girth, even a three buckle one if your horse does not get on with separate girths. I don't find my saddle any less stable using them at all but I probably would not recommend them for a beginner just starting out as I did find that my saddle did shift a bit when I had my friend's daughter who had never ridden side saddle before, try my saddle as beginners tend to move about too much. I even jumped that 2' jump in it at the Burbage Diamond Jubliee show last month and it was fine.
I've always started using a Lemieux sheepskin half pad with my off-side side saddle to prevent another bursitis bump on her withers since she is prone to them. I don't need one with my Mayhew, only a thin quilted pad but it's better to be safe than sorry and Hattie likes the sheepskin as well. It also has shims so I can adjust the fit of the saddle with the change of seasons as well. The white one I also use with my astride saddle but also have a brown one for showing in.
So far so good with the change of tack!