Questions on imitators

[harpy]

I am about to begin construction of my first vertical. I am leaning toward a 20 gallon inverted, and putting imitators in it.

How many imitators should go into a tank of this size? Is it always best to keep imis in trios, pairs, or groups? If the answer is groups, what size vertical tank would be ideal?

I love the idea of successfully breeding these guys, and having them raise young on their own. How likely is this in a 20 gallon vertical?

One last question - what is the best/most effective lighting strategy for this tank?

Thanks,

Greg L.
Temperance, MI