If using a live one, assuming you can find a 2lb peanut, your standard bridle rig with floss and a big circle hook would do. However, your trolling speed would probably need to be slowed down which would make you cover less ground. In our canyon areas I would think that would be less effective than covering lots of ground at higher speeds. In other parts of the world with higher numbers of blue marlin concentrated on lumps and underwater sea mounds it would be very productive.
If using a dead peanut, sew the mouth/stomach/gills shut like a spanish and use a 2-3 oz chin weight or make it a skipper. the downfall to this method is that a dolphin looses its color so badly after it dies it actually looks very unnatural in the water. With a spanish, you can throw them in an icy brine right away and preserve their color. Id say its worth a try and ive often thought about doing it. I guess just try to take care of your bait as soon as you throw it in the boat (minimize scratches from line/boat/hands). With spanish I throw them right into the brine bucket without ever touching the fish.
I think a peanut dolphin under a kite would be killer if you were willing to spend the time drifting the canyon walls during the day. It seems that now days with the prices of fuel that less people want to make that run and experiment with new types of fishing, instead, relying on the standard techniques.
Good luck if you try, id like to see some pictures of how you rigged it