@ustk Sure thing!
Anecdotally, all multimedia gear, audio cables, etc. are sold by the foot in this country. So that's likely the unit that your end user is expecting. The only thing we buy by the yard is fabric, haha.
Edit: Feet with a decimal point is likely the best option here until you're to measurements that are less than 1 foot. Sub-foot measurements should be in inches with a decimal point. Not ideal considering how all of our measurement devices are marked, but your average consumer would know how to navigate this. Ideally in sub-foot measurements, you round your inches to the nearest 1/16" unless that level of inaccuracy breaks functionality.