I have a quick glance at a photos and it look like the rear triangle is hourglass shaped, meaning that there may be a possibility that a bigger 650b tyres may not fit well.
A friend has some wheels, so I’m going to try them at some point, I’m hopeful but not sure. Did some quick measurements, 325mm from axle etc, hard to tell without removing bike from our storage / having the wheel off etc!
I have a quick glance at a photos and it look like the rear triangle is hourglass shaped, meaning that there may be a possibility that a bigger 650b tyres may not fit well.