I used a Marlin-supplied clutch master cylinder and hose and found these notes from my build diary:
Clutch hose had both ends metric (M10), but clutch master cylinder is 3/8 UNF so ordered a new cable from furore cars.
And their hose did the job no probs. I agree with Ian that you need to get them made to the right length, unless you can do it yourself. Fortunately not too expensive, relatively of course