Maybe a bit late, but enjoy your day in Glasgow.
Glasgow Central has lots of 156s, 314s and 380s. A few 320s coming in now on the Lanark runs from what I understand. It's probably got the greatest variety in liveries and TOCs as well, with the longer distance trains. Unfortunately, most of it is now behind barriers, so whilst you could previously have camped out at the end of (the now demolished) Platform 11a, it's not quite as easy any more to get shots of the impressive approach tracks. If you'd known in advance, you could perhaps have taken a tour of Central station, which is very impressive station with lots of history (these are amazingly popular and are fully booked many weeks in advance!).
Queen Street has 158s, 170s and the occasional 156 upstairs, but again all behind barriers and not much of an approach for photos. Downstairs isn't great, due to light and the big wall in the middle. Everything that goes through GLQ LL also goes through Hyndland. I'd agree with Hyndland being a good station. With trains every few minutes and good opportunities for photos at both platform ends (and no barriers!), it should be a good place to spend a wee while. You'll get 318s, 320s and 334s.
For travel, I'd recommend going out Ayrshire and Inverclyde way to get some nice views of the Clyde. Kilmarnock is also a nice run, and an alternative route to Ayr. Helensburgh is another recommended journey.
Wherever you end up, enjoy.