As far as cleaning them goes...check out this link. There is a "how to" on the left side bar. We cut the 'loins into 1" sections and deep fried them. I think they would be good in a shrimp/crayfish boil also.
My experience with gar is that they like to cruise the top on sunny days.

Guess it helps if I actually put the link on...

http://www.illinoisbowfishers.com/

Good Luck. Let us know how you like them.