There are new ways of putting on indicators, particularly to make them adjustable on the leader. But for Tongariro etc I still tie my own on to a clip using quality glo bug yarn in different colours to suit different light conditions. Quality yarn is important, I believe. You get what you pay for.
My method - which seems to work pretty well - is based on two key things I was shown once by a guy who fished regularly at Otamangakau, sleeping overnight in the back of his old Nissan Terrano. He had perfected the art of indicator nymphing there, and his sailed amazingly. Even if you don't tie your own, the following works well on commercial ones of a similar design.
1. Use a standard pocket hair comb to vigorously comb out the yarn after tying. You'd be surprised how much extra yarn comes away - stuff that would glug up and get waterlogged if you didn't comb it. That leaves nice, untangled wispy yarn that can be clipped to shape.
2. Dunk the whole thing in the lid saucer of a bottle of Liquid Mucilin - designed for dry flies - until it's nicely soaked. Remove and squeeze out the excess back into the bottle. Then dry the indicators on a paper towel overnight. I do a batch at once.
With these two things done, the indicators shed water extremely well during casting.
I keep 3-4 fresh fluffy ones in a little screw top plastic jar (very well cleaned ex Marmite jar etc) ready for a day on the water. If after a hammering they start to sink, they get replaced by a fresh one. Most of the time, one indicator is good for the whole day.
After the end of the day the used ones get re-combed and re-treated. They last ages if tied well and with quality yarn.