a few breeding questions regarding bettas.?

[cinnafab]

I am preparing for my frist spawning, im currently getting ready to start conditioning, i have been doing research, but these are a few questions i have nto had cleared up.

1. is it ok to use a 30 gallon tank, full about 5 inches high with a divider in the middle? that way they have closer to the regular amount of room people use?

2. is a bubbler really necessary? if so, why? and can i use my normal filter with a nylon over the end instead of getting a sponge filter?

3.i have 2 possible females for my male who is a double ray crowntail (marble-purple, white, and red) the two females are 1. a double ray ct female who is black and purple with lacing (would i get some black marbles in there? or what?) or the second female is purple and white but she is a half moon... i could breed with the goal of eventually creating halfsuns? would i get combtails in the first generation or randomness? anyone know? both the females are from the same breeder if thats any help...

all help is appriceated.