this plant grows nutso.. if left unkempt in unlimited space, they can reach a meter wide, with leaves as large as a dinner plate.
the best way to train it, is to keep the roots under control.. restricting the roots will keep the leaves small and compact. Ive developed 2 good ways to do this:
1) get a stanley knife blade, wedged into a slit on a thin bamboo cane, you can ziptie the cane just above the blade to stop splitting. (this doubles as a pretty decent algae scraper as well!) chop down into the substrate about 3 inches away from the bulb in a circle. Do this once a month or so. This will keep the roots from getting out of hand, and encourage the plant to root more locally to the bulb, restricting its supply of nutrients thus slowing down its growth (which is desirable!)
2) when you plant it in the beginning: take a 5 - 6 inch flower pot, and carefully cut the top off to a depth of a little less than your substrate depth. Plant the bulb inside this ring.. this will be similar to planting a terrestrial plant outside in its pot to control its root spread (such as bamboo). This is a pretty good way if you have a jungle type layout which is hard to find the bottom of plants! but obviously you have to think about it right at the start. If you already have an established plant, do method 1 then put the ring around the bulb afterwards, you can cut it down the side so you dont have to loose any leaves or risk breaking any foliage.
Both these methods will keep the plant 'pot bound' which is prefers, Ive managed to get them to flower under these conditions far more than I can if I let the plant go mad on its own accord. Smaller leaves will create much less shadow and allow more leaves for a given area which, to me anyway, is more attractive.