>Do you think that springtime would be a better time to requeen then fall ??
No.
>1. more queens avalable,
But theyare are NOT more queens available. Spring queens are expensive and hard to find. If you want norhtern queens, you really can't get any until the end of June.
> 2. Queen easier to find because of fewer bees in the hive.
Find them and mark them in the spring so you can find them in the fall. :)
> What are the advantages of fall requeening over spring requeening ??
Better mated queens (more drones available), more queens available, cheaper prices on queens, availability of Northern queens.