I have a fully engineered highland greenhouse; good old wood-and-glass construction, and I am situated in the Pacific Northwest, where summer nights always cool off to 55F or cooler, making greenhouse climate regulation for Nepenthes a relatively easy task.
And yes, its perfectly reasonable for a badly damaged plant to take a full year to build up to a plant of that size. When I saw that photo, I thought to myself what a great job you did bringing it back to health. I cannot offer you suggestions on watering, since it really comes down to your climate conditions and the density of the potting mix, etc. My soil mix is very light and open and I can water daily if I choose and there would still be plenty of air spaces in the mix. Dense, slow-draining soils will require much more careful monitoring of soil saturation. You have to figure out what works for your conditions and your soil mix. Unless you are letting the soil dry out between waterings, then more watering isn't going to speed up growth. The only thing I have found to increase rate of growth is the return of longer, brighter spring days and daytime highs above 80F* coupled with nights around 52F.
*but not exceeding 85F if at all avoidable.