We spent 8 days in Scotland this summer, covering most of the country. Glasgow by far was the least interesting. On the day we flew from Glasgow to Iceland for leg 2 of our trip, we spent a few hours at the art museum (building more interesting than its collection), the maritime sailing museum, and the indoor skiing (which is even smaller than the one in Dubai, but still fun to do for an hour or two, unless you normally ski blacks, in which case it will be boring). I don't recall seeing or hearing about a ferris wheel there in the summer.
The military tattoo is absolutely amazing and one of the highlights of our trip; I've never seen anything like it, and the setting in front of the castle, with fireworks at the end, was phenomenal. Cheap tickets sell out early, so make sure to book early if you're planning to go. In the show, there were no women singing, but there are women dancing in groups in various parts of the show.