Rob,
I didn't grow these from seed but even the bulbs took a couple of years to "settle in" before they started to flower. The conditions must contribute to the flowering but sometimes they flower well after really hot summer sometimes after a wet summer - I can't figure what the best conditions are!
This year Lycoris radiata has only 2 spikes [on 2 separate clumps - one in sun and one in shade]
Two pics of a "clump" of Lycoris elsae - just open on the weekend - in full sun;
cheers
fermi