I don't see why it would be a tricky job to rebarrel to the 350 Legend, other than finding a smith with a reamer and finding a good barrel of proper diameter.
35 caliber barrels are available but much more difficult to find.
If you're looking to get a smith to do this for you for the present hunting season, Good Luck.
If you really want to get such a job done, purchase a good quality barrel, purchase a reamer and approach a smith to do the job for you. That will bring costs down.
This cartridge headspaces on the case mouth so that won't cause any issues.
The next big issue is that those cartridges aren't commonly stocked anywhere in Canada. If you don't handload???????????