For fishing the slide, I carry two sizes of swimbaits, 3.5" and 5". Assorted size leadheads range from 1/2 ounce to 2 ounce. On the way out, ask the deckhands what size they recommend for fishing the slide.
As to what color you plan on using, light conditions have a lot to do with it. Have something bright rigged up and something dark.
Before you leave, superglue a couple different color and size combinations so you will have some ready to tie on. Its a whole lot easier to get this ready before you go. Check out
www.fishtraplures.com for info on how to rig and fish them. Tons of helpful stuff on Barry's site.
If you read some of the fish reports, indications are that the Tuna are still chasing smaller baits, and primarily on the surface. That should tell you something about the size of the swimbait that might work best and the size of the leadhead too.