Cantilever set up help requested

Put a cantilever back on the front of my masi cross. I set the straddle carrier as low as I could go while still having good tire clearance. Am I doing it right? Riding around my 'hood my steel fork shuddered. Is that the cycling gods telling me to get modern and put a carbon fork on there or should I deal with it?

I'm doing Cattle cross so I'm going to check how well i tuned the brakes there, and if I'm lucky, i'll fix it if there's a problem with it.