I'm not a mod here, but some thoughts from my experience moderating 7 sites ranging in size from tiny beta to 15th biggest SE site:
Time-wise, a site this size shouldn't be an issue. While my time varies across my sites, I tend to put in a bit of moderating first thing in the morning before work, some at lunch-time, and then I'm online in the evening so can attend to issues that crop up while I'm doing other things. One of the significant factors in making a site easier to moderate is a committed core community - and Mechanics has this! Another is a well defined, and community-supported scope. And Mechanics is also strong here. So I'd expect Mechanics to take maybe 30 minutes a day on core activities, plus whatever is needed depending on escalations.
Moderating really impacts your ability to answer questions. Not just because you spend time just going through your mod actions each day, but because you find yourself holding off on answering or responding to give others a chance, as whether you like it or not, the little diamond by your name is noticed, and often readers will assume an answer by a mod will exclude all others.
Some people will decide they hate you and everything is your fault. Just because of the diamond. And some of these people will be really, really nasty. Doesn't matter what you do - it'll happen at some point. You need a thick skin, and the awareness to just back off and walk away to take a breather occasionally. You'll also need to not be too proud to ask for help when it does become upsetting, painful or difficult.
Working with SE staff, and mods from other sites gives an excellent opportunity to learn, network, widen your experience, and community promotion activities can be very rewarding.
The visibility of analytics that you get as a mod really helps you see the impact of specific activities. I enjoy that feedback as it can directly improve the site.