I would have two people in boat, one up top running the allen wrench and the other under the dash with small hands reaching for the little wing nuts. Take them all out and it will pop right out, you may need to cut a couple zip ties to get full access.
I am going to use aluminum plates and pop rivet them in place where the wing nuts were. Then drill and tap for the hex head cap screws, if it works should be much easier to remove next time.
I also wanted to share this document I found while talking to Faria