Hi John F.
The Rapala X-Rap walk 13 is a medium sized stickbait. The walking action is absolutely deadly, but the problem is that it is a bit subtle and cannot draw fish from a long way away, or up from the bottom in deep water.
For this reason it is a good action to use in water of up to 12 or 15m in calmer conditions. Kingfish species and Queenfish in particular are crazy for this lure.
When fishing in deeper water offshore for Yellowfin Tuna, the right way to fish it would be to crank it back reasonably fast with the rod tip held almost upright, give the tip a bit of a nodding action while retrieving. This will cause the lure to splash quite a lot and still get a side to side darting, almost snaking action. This makes it easier for the tuna to find it and will definitely result in them smashing it, they love that action.
I like to rig this lure with a single hook on the back, with two split rings so that it rides hook point up. I use two singles back to back on the belly, held with insulation tape or a cable tie. It is good to use short shank, wide gape hooks for this purpose.
Good luck with your birthday lure, I am sure that you will have a lot of fun with it!