I dont know, but when I was looking for the advantages of the pictured system I guessed that a smaller frame would result in less clearance between the crank / your heels and front of your panniers as the rack would in theory sit further forward.
Thinking about it a bit more though that's probably rubbish as I guess the rear triangle and thus the rack mounts must be in roughly the same place no matter what size the frame is to fit the rear wheel in so the rack should be in the same position relative to the cranks no matter what.
With my big clown feet and long cranks I have to make sure the panniers are as far back as possible or my heels catch them when they're fully stuffed with treasure, I guess though that a smaller rider will probably use shorter cranks and have smaller feet, so it's possibly less of a problem?
I ride 172.5mm cranks. TBH, crank length is whatever comes on the bike -- I have different crank lengths on different bikes, because they only vary by a couple of mm either way, and frankly my shoes are not tight enough for my feet to be in constant relative position, so I don't think it matters that much. I do have trouble with the heel clearance with panniers on some bikes, especially my On One Pompino (medium). The rear triangle much accommodate the rear wheel, but I suspect the seat tube angle variation may affect things.
I initially set Hamish (the PX) up with a Tortec ultralight and a Carradice rackpack, and it just didn't work. There's not enough space between the saddle and the rack for the rackpack to be far enough forward, so the velcro straps were tightened at an angle, and the pack dangled precariously off the end of the rack, obscuring the tail light. Panniers would have been fine, I'm sure, with some finagling, but I don't want to ride with panniers all the time.
I've ridden fully loaded on my Orbit, and I also found that putting all the stuff for a 2 week camping trip in the rear panniers unbalanced the bike significantly. That's why I used to ride with kit in low rider front panniers to put more of the weight on the front and stabilise the steering. The PX doesn't have rack mounts on the front -- apparently the Selcof gravel forks are compatible, but would change the geometry of the bike -- so I have no intention of using it for the kind of kitchen-sink touring that I used to do. I'm refurbing my Orbit for that.
And possibly embracing a more lightweight approach!
This system really comes into its own for bikepacking/saddlebag rigs where there isn't enough of a seatpost-rear wheel gap to fit in a saddlepack (my Pompino has eaten a Carradice saddlebag, which is why there's a rack on him now), bikes that don't have frame mounts for even a lightweight rack, and for people who want to be able to remove their luggage carrying system easily (or use it on more than one bike without a lot of faff). If what you want is a fixed way to carry enough stuff for camping to be a home away from home for weeks on end, and you're not that fussed about weight anyway, you're probably looking at front and rear rack and panniers. And probably not a PX Hurricane.
Sam