I use the mini hipster for Disney, too. The straps are too long, but I just knotted mine at the top and it worked like a charm. I'm not a sewing person either.
Also, I don't think you could fit a regular size spray suntan lotion. It might fit length-wise but would be pretty bulky and wouldn't really work width-wise. I've thrown a 3 oz size (carryon size) sunscreen in my hipster no problem.