I don't know what the limestone footing is like, but I'm assuming it's like walking on pavement or bedrock. I don't think I would want to be doing arena work on that kind of surface without something on my horse's feet. But not due to wear, due to traction. Any horse I've ever ridden is not confident at more than a trot on slick ground and for corners... hmmm.. never mind jumping.
I know you said you tried Cavellos on her and that they rubbed the sole. That doesn't make much sense to me, but I have never seen Cavellos live, in person. Still, it sounds more to me like either the trim wasn't right or the boots didn't fit right. I would be inclined to try a different boot. Some people's farriers stock various sizes so their clients can try something before they buy.
Also, I really doubt that the hooves are wearing faster than they can grow. It's likely a transition time for her and boots would help you to ease through that transition and maybe keep her barefoot. Generally speaking, with a proper diet, the hooves will grow as much as they need to for the given terrain but it takes a while for that to show. How long, I unfortunately don't know. I would suspect 3 months or more.
If her feet are chipping, usually that is a sign that the hooves are too long and in need of trim. If now there is nothing to trim at 7 weeks, they should not be chipping anymore. If the trimmer says there is nothing to trim, but the next day there is fresh chipping, then obviously there is indeed something to trim.
How would you feel about posting pics of your horse's feet?
Below is a video of the arena just so you can get an idea of the footing. As for the boots, I measured her and she actually has exact circular front hooves and I purchased the boots that she was an exact measurement for, so at least in that respect she was fit perfectly. However after I purchased them, I did hear from others than the Cavellos rubbed and sure enough, they rubbed on her as well. So perhaps it just is the brand and/or how they are made.
She's been at this barn for a little over 3 months now, and the longer she's here, the worse her feet are getting. So I'm not sure how much longer I can leave her barefoot without some lameness starting to show, but I can tell you that the longer we go in this footing, the shorter strided she is becoming and the less she is tracking up. She's never been on footing like this before consistently, she's always been in a deeper footing sand arena, so this shallow footing limestone stuff is definitely a big change for her.
I've had her for almost 4 years now and I've never seen her hooves this ripped up before. Previously she could go anywhere from 6-8 weeks between trims, and she might have 1 or 2 small chips around week 7 or 8 with plenty of extra hoof past the white line for the farrier to clip off.
Now about 2 weeks after the last trim, she is chipped up so badly it looks like I never get her hooves done, and even 7 weeks out, she has barely any hoof beyond the white line. Her frog is also changing, becoming very hard and flat, seems to be wearing down.
I planned on getting some photos tonight that I can post on here for everyone to take a look at. The farrier is coming Thursday so I'll be picking his brain on the subject then once he has a chance to look at her.