what type of gar are they? are you catching them to eat or are you planning on releasing them?
where I'm from we have longnose gar We just use a hook less lure made from nylon rope when they bit it it gets snaged in there teeth.
If you want to release it take a 1x4 board 2ft long draw a line down the center length wise 2 1/2 inch in from one end drill a 2 inch hole at 4 1/4 inch drill a 1 1/2 inch hole at 5 1/2 inch drill a 1 inch hole.. then cut a small V notch from the end through the holes . make a 6 inch long 1inch wedge. attach it to the board with a string or chain. when you catch a gar slide the line and its nose up the V to the hole that match the size of the gar pull it tight into the hole using the line slide the wedge in its mouth and work it down to open it... you can safely remove the lure.once the lure is free hold the board out over the water remove the wedge and it will release.
have a great fishing season