Yeah of course its do-able You have to find a routine that works for you and your schedule. Me and my boyfriend both differ on the times we have our shakes but that's because our working day is different. If you do that for a few days and don't think it's right for you then play around with it a bit.
Personally I wait until I feel I need a shake. I started off having them too early and felt really hungry during the day. So I usually have one about 11am when a mild hunger pang creeps in. I then won't have another one till around 3pm and then again at 7pm. It fits in with me as I wouldn't normally have dinner till around 7pm anyway. But sometimes I forget to have my second shake and just have it when I remember!
Good luck to finding what works! What you have suggested seems absolutely fine to me xxxx