Nope, shape doesn't matter. Both the square and the S both have (9) 360° sprayers. As far as nutrients go, I'm not using any...no nutrients or cloning gel/powder. There's no need for them. The cuttings will root just fine without them, I am the proof of that. I'm sure there's no harm in using a rooting gel before putting them in the cloner, but it's definitely not necessary.
I used just plain ol tap water, not dechlorinated or anything special. The heat the pump puts off is plenty enough to warm the water. I just spray the few leaves that I leave on the cutting maybe once a day with plain water. They aren't under any lights (they're actually in a pretty dark garage) there's one window but it's nowhere near the clones. Just make sure you sterilize everything you use...the razor, the neoprene, the net pots, and of course the bucket. I use alcohol swabs on my razor each time it touches a different plant.
FYI: Don't try to use scissors to take the cutting. No matter how sharp you think they are, they will still damage the cut end. Scissors actually "squeeze" the stem you're cutting and you won't have a clean cut. I personally use a box cutter. I will use scissors to take the initial cut and then use the box cutter to make the final cut. Also, you don't even have to have a 45° cut either.