Having owned this frameset, I can tell you that any brake you buy will have the brake pads overlap the inside of the fork. Any sufficiently nice brake should come with cartridge pads, which will get you a bit more clearance - just a couple of mm, but the pads will certainly clear a 33 mm cyclocross racing tire. But yeah, a fully inflated 38 mm tire will be a tight squeeze through the brake pads. You can probably force it through, deflating it will help. You will be able to make it work one way or another, I’ve done it myself. As I mentioned in another thread, I strongly advise a mini-V brake over a cantilever, and the good ones come with cartridge pads. Anyway. I loved my canti Swiss Cross. It’s the best-riding bike I’ve ever owned. It has character for days. But it does have its fair share of… let’s not say flaws, let’s say “quirks.” The aforementioned fork shudder issue is one of them. With the brake pad clearance, you’ve found another. You’re going to find more. Enjoy!