They fan them with the pectorals, the ones on the sides. Ventrals are the ones that hang down.
http
/www.webrbiz.com/angelfish/amh.html is another good site. What works for some people doesn't work for others, probably half is trial & error.
The biggest 2 things you need are a place to sell 300+ angels, and enough tank space to grow out that many fish. I have 250 gallons split between 10 tanks for growout of 1 spawn, that much water is needed to get them to sellable size, dime to nickle body.
Find at least 3 places that want them, the place that says they'll take 100 when they're ready, will have gotten in an order when they are ready, and tell you to call back in a month. I've had it happen, thank God there are a lot of shops near here.
Once you have that figured out, the slate idea is a good one, pvc pipe works too. When you are ready to pull a spawn is when they will spawn on the filter intake, heater, or some other unremovable object. Put something removable in front of those sort of thing.
The placement of the airstone isn't as critical as the force of the stream. Some say have the bubbles directly on the eggs, some say near. The important thing is that it is a gentle stream, you don't want too much turbulance on the eggs or wigglers.
Anti-fungals are trial & error. What works for me is 7 drops per gallon meth blue, 3 drops acriflavin+, 4 drops maroxy. Some people have used hydrogen peroxide with good results.
Water changes on a fry tank do s l o w l y !! I trickle water in with a large cup with a small hole, 1/16", drilled in it, with water from the parents tank.
A brine shrimp hatchery is a must, liquifry, frystarter, or any other crap rarely works. You start to lose fry, ammo takes off, you lose more fry, end up with 3 living fish, all of whom are defective from the ammo. Been there, it sucks.
Wow, this got long, feel like I'm writing a book. Any other questions PM me, I feel like I'm sucking up bandwidth!
HTH
Tolak