I think any heavy and SLIM flies will work. I love high sticking as well as mixed with European nymphing styles. If you are a big fan of high sticking, you will love it and learn it quickly!
I would say CZ nymphing is very "aggressive" type of nymphing. Unlike wetfly swing, You are somehow "precisely" leading your flies in to a certain spot/zone. I usually pull (lead) my flies into the route I already "designed". At the end of the drift, I would let the flies raise up and might take some followers.(just like regular indicator fishing). I remembered Velvadi mentioned that you want to do some "micro hook set" when you think your flies are drifting by a hot zone.
When said "Lead the flies", I think the important thing is "feel the flies and feel the bottom". I think I like to feel the weight of my system and the feel they bounce along the bottom (every once of awhile). When I feel these two things, I know I have the authority to control my system...speed/depth/direction
The main difference between CZ nymphing and high sticking is "leading the flies". 1) This means I need to "pull" my system slightly faster than the current. 2) Also I need to keep the flies deep and contact with the bottom. That is the reason that heavy and slim flies come into play. If my flies or system too light, I won't be able to "lead" the system. The current will divert my flies all over the place. (Usually I use this CZ nymphing in a relative fast current or pocket waters; I use high sticking in a relatively soft water... cause I don't have confidence to lead the flies right...).
Beside the weighted nymphs, tippet size is the other important factor to me. The fine long tippet will help your system "cut through" the current and give you more authority to lead the flies. Sometime I use 4x or 5x tippet straight. By using fine tippet straight, I also can reduce the flies weight (more natural dangling of the end fly). Also the current will have less impact in disturbing your system.
Spey is a style of casting, single handed or double handed rod are all effective by using spey cast to deliver the fly. I did some spey casting ,experimentally, from 3wt 6'6 to 7wt in some tight vegetated creek, and it did work great.
There are two major types of spey casting, it was classified depends on the "anchor” types. 1. Traditional spey: the anchor is "kissing the water", is type of touch and go, minimized the stick of the water tension.(e.g. Single spey and snake roll cast) Also, the whole motion of the cast is continuously exercised. Keep the line tension from the start "lift" to the "fire out". (Rio Grand Spey is the line suitable for this type of cast) 2. Skagit style spey. This type of spey use "water borne anchor", use the maximum water sticky tension to load the rod. The sequencial motion of this cast can be break down to several parts. (e.g. Double spey, snap T) ( I was very very impressed by Al Buhr's Skagit casts). It also very easy to cast a heavy shooting head, use several “broken down” motions to bring up the heavy head and also "increase" the water tension to load the rod and fire out. I start to use this type of casting not long ago and really love it for casting heavy flies. I think skagit cast have it's advantage in shooting streamers. The reason I say that is, you shoot out a long running line, and work your fly all the way back, then use the heavy head to shot them out again. Almost no false cast involve, it works very efficient to me. (Skagit line, heavy and short shooting head work for this type of cast)
So, I guess my answer is spey can do it all...but... For big water, I use double handed rod, combined with different lines. it save energy. For small water, I use single handed rod, combine spey and overhead casts. Depends on the creek condition. (carry a 13' stick around in a creek wasn't fun...) This is just my opinions...for your reference. (yuhina's response in WFF.com)
I am a biologist grew up with a fishing rod in my hands. I have been fortunate enough to embrace my love of art and science in my career. Most of my free time were well spent in the nature, either studying bird behavior or chasing variety of fish with fly rods. My favorite art medium is watercolors, I love the natural and spontaneous feel created by watercolor pigments. I am currently a post-doctoral research fellow at Harvard University. Welcome to my website. Mark