Let me buy the watch first. I’ll go to town tomorrow to have a look at what the store has, see what my mom might like, and try to measure the inner diameter with calipers. If it looks like 30mm+, then yes that might be a good idea for a clean job. If it’s under 30mm, it’ll have been wasted.
Ah! And I thought my mom was forgetful 
👇
So, unless you’re reasonably sure you’ll get the greenies very soon, 3 yellows then.