I bought a stopwatch and fitted it to my kneeboard for a while but being tall found that any added appendage anywhere just got in the way and irritated me.
My instructor took me off to the local supermarket during his lunchbreak and pointed to the most hideous looking digital watch Id ever seen.
Big buttons, big numbers, easy to use and read!!! That was his advice and I never looked back, Ive still got it somewhere.
Keep it simple