Oh, I didn't know Aleene's had a spray sealer! For the record, I personally love Aleene's products so I would give it a try. I'd test it out on something you don't mind potentially going sticky though.
And as another alternative to Mr. Super Clear (which I can't get either) there is always Testor's Dullcote. Never had an issue with it and I live in a climate that makes everything sticky, lol.