The capacity for Midway Mania is too low to properly handle FastPass and as a result too few are distributed to meet demand. Only the few who arrive before park opening and race to get one first receive one of any value. (If you're picking up a FastPass at 11:00 am and it is not valid until 8:00 pm it's not very helpful.)
I think the one flaw in the advice in this article is that if the line for Midway Mania is 45 minutes or less you should ride it. Don't get greedy looking for 20 minutes or less. This park has a severe shortage of quality attractions and you'll have plenty of time to ride the other rides even with a 45 minute wait.
I changed that recommended time on TSMM about five times before I decided to go low and just see what people said. So let's throw it out there -- what's the longest a TSMM standby wait time would be before you wouldn't get in line right then?
Also, to clarify: On these pieces, I'm including the top five or so attractions in a park that get an average 10, 9 or high-8 rating from Theme Park Insider readers. GMR has a 7, so that's not one I'd include as a "must see" in the park, based on readers' average ratings. It's a nice get, but there's much in the park that readers collectively have decided is more worth seeing first.
The Great Movie Ride is a worthwhile attraction for anybody who hasn't been on it. It's exclusive to only this park and this high capacity ride rarely has a long wait. Special props go out to the actors on this ride, always amusing.