You can always go down to the RAC counter a few days ahead of time and talk it over with them. I've never needed to use them that early, and never been there with more than 2 people ahead of me. It's also never taken me over 10 minutes, from when I get in line (2 checked bags). It's been pretty efficient.
To what purpose would you go and talk to them a few days before?? You must be completely finished, boarding passes in hand, luggage tagged and taken away, no less than three hours before flight departure. If the OP's flight departs at 8:30, they HAVE to be done by 5:30...and it would be nice to be done by 5:20, just to be on the safe side. I would imagine that if the OP is standing there, at the RAC counter, at 4:55, they will be first to be taken. And then they should be walking away, boarding passes in hand, by 5:15.
Generally speaking....
If you wait until 8 or so, to head down to check your bags with RAC, you are going to most likely run into a lot of people. The vast majority of people flying out later in the day, head to RAC on their way to a park....they get rid of their bags and head off for a few hours or so in a park before heading to MCO. I always get to RAC by 7 on my checkout ay...hate having to stand there while those in front of me redistribute their belongings due to the bag being overweight. And yes, it has happened to me at least 4 times.
It should only take 10 mins to get done at RAC, but there are always glitches in the system or someone who doesn't understand the proceedure, or even a long line in front of you. I have seen lines that are about 10 groups long...but that was around 8:30ish.