Pam,
Normally, it's a snap. Dig a furrow about four inches deep, place part of a seed potato (as long as it has 2-3 'eyes' on it), add a sprinkle of 20-20-20 fertilizer and cover. Maybe apply a bit of nitrate when the plants are about six-eight inches tall. Pull dirt around the stalks and wait for four-five months to dig them. They will grow about a foot tall before dying. Supposedly, if one keeps adding dirt, they will keep growing, probably until the first killing frost.
I don't have that luxury - I've got to grow it by August 1. Normally, I would not use much fertilizer because it makes the potatoes less solid (increases water content) but in this case, the plant is for show - I will explain that normally the plant would not be this high.
Perhaps Superthrive or similar would work. In re-reading your plant hormone thread, you mentioned that perhaps auxins were responsible for AJ's larger plants and I also read where Naphthenates have greatly increased bean production.
Next year, I'll be better prepared. I'll save a few potatoes from this year's crop for seed, plant them in January and avoid trying to use a lot of chemicals.
Mike