There are probably different methods to try. See this link for some discussion. I plant 12" apart in rows that are 18" apart. I plant in a 4" deep trench, then hill a month later, and hill at least one more time after that. Tom Wagner always said with TPS seedlings, hill them repeatedly. It is not too much different than with tubers, but the plants are smaller and more fragile, and take longer to get large. Some never get very big.
http://tomatoville.com/showthread.php?t=12908