Camprax,
Please be aware that transfer to LHS is not "automatic" - regardless of demand. There are some who think that as soon as they hit the magic 3000 hours then they should automatically be assesed. Doesn't quite work like that! The factorised hours are just one of many pieces of the jigsaw. Your attitude, sim checks, line checks etc are all taken into account.
You will be assessed as to your likelyhood of being able to pass a Command course should you get the opportunity. Only if all the above "boxes are ticked" will you get a crack at the LHS upgrade.
Your Command Training starts from your first day in the RHS! FO's have a responsibility to "train" themselves with respect to knowing the books, policies, procedures etc.
Good luck with whichever path you choose.
Regards
A4