Echinodorus flowering/Kribensis


My E.Maior has been flowering for more than a week already.
I read that one of the way to cultivate it is by planting
the seed. Anyone know where can I get the seed from the 
flower stalk? Thanks.

Oh, one more thing. I just got two pair of Kribensis after
more than 6 months search. Are they top, mid or bottom
feeder? How many caves should I create for the 4 of them?
Thanks again.