Well as far as training goes most of it will probably be with a Master or through classes. You can do some self learning but it is limited to basic stuff. There will be a new rank advancement system but it hasn't been released yet so I don't know anything about it.
Sorry it took me so long to get back to you...I am real busy during the day. My Sith will have an apprentice after the skip, sorry. However about your questions on making a Sith what can I do to help?
Hey, Good to meet you. Actually all of my characters are either in limbo because of the upcoming timeskip and I won't be RPing any of them until it takes place. But afterwards I would be able to. What do you have in mind?
Well, I'm known for liking older people, so I'd say the older the better. lol
Even with the time skip, you don't have to age your character the full ten years if you don't want to. Just make sure s/he acknowledges the events that have transpired in the ten years.