If you look at one of my earlier posts in this thread (Post #8) you will see a photo showing a plastic shoebox size tray, full of this species. All of those plants are planted in a mixture of APS (Shultz Aquatic Plant Soil) and rinsed silica sand. Usually I kept this tray full of water - this is a rare moment when the tray has only a very little water in it, but the pots have not dried out. If you decide to grow yours wet, don't forget to balance the extra moisture with lots of light.
My experience is that this species does not seem to benefit from free calcium in its substrate - I tried growing some of these with various calcium-rich media ingredients added, such as gypsum, coral sand, and ground shellfish shell. All plants of this species grown with additions of these media, grew less vigorously than those without. They will grow in sphagnum peat moss, but the peat moss decomposes quickly and must be replaced often.
Pinguicula moctezumae does not appear to be a heterophyllous growth type species, only a homophyllous growth type. Though mine tolerate short periods of being almost dry, they never change their growth habit.
Those Pinguicula from truly temperate climates, some are even boreal, that form Winter hybernacula, exhibit a complete and true dormancy. As I understand dormancy, it is a period of suspended growth (true dormancy = a period of virtually no growth). Perhaps the heterophyllous group of Pinguicula could be said to have a Winter period of semi-dormancy, because, even those that form bulb-like Winter growth, are still continuing to grow more of their smaller, scale-like succulent leaves. Most, if not all of these species even bloom from their supposedly "dormant" state. Yet none of the Mexican species actually cease growing, so despite several books having been written, incorrectly describing the Winter state of heterophyllous Mexican Pinguicula species as "dormancy", there is no true dormancy, only perhaps semi-dormancy.