Hi Ken,
Is your Nepenthes alata the one that develops red streaks and spots? It looks really good so you must be doing something right.
All Nepenthes need a loose potting medium that stays wet but doesn't hold water, ie: sphagnum moss. You could add perlite or lavarock to it but it's not necessary. Just keep it loose. N. alata is a highland pitcher meaning it can take some colder temperatures. Lowland pitchers drop dead at temps lower than 60. If the pitchers don't develop properly and dry up, the plant needs more humidity. The kind of water really doesn't matter unless its really horrible - it's more a question of how much water. They love overhead watering as it adds humidity but hate sitting in water.
I have just one Nepenthes: N. ventricosa. I chose it because its a highland pitcher and my greenhouse often drops to close to 50 degrees at night. Also, its a very compact grower; it will never have branches 10 feet long (but your's will).
How come we don't have a carnivorous plant forum?
Daisy
