I've been reading up on geraniums prior to planting some seeds myself. They frequently vary quite a lot from their parents if they are home (or park) collected. I know this from experience too, since my attempts at growing purple leaved varieties produced some green, some purple, one black and one with perlagonium-like rings of red on it's leaves. More fun than getting them pre-packed if you ask me
This year I am going to try and grow seed from a scented variety that was sitting next to the purple ones. You never know.
Germinating seems to be quite easy, and I agree about the sowing time - early spring worked for me.