This answer is ideal if raiding with a guild.
You should stay Tier 1 8/8 for set bonus and funnel Tier 2 8/8 to another hunter (Assuming they all don't have Tier 1 also)
One hunter in the guild at a time should be funneled Tier 2 until 8/8 for the set bonus. Extra pieces being distributed to either the 2nd hunter in line or evenly to the remaining hunters.
Do not remove Tier 1 until Tier 2 is completed. The damage boost is drastic and honestly if one hunter gets Tier 2 8/8 it benefits all hunters.
Edit: I think it answers question 2 already, but use Libram on Tier 1. By the time you complete Tier 2 you should be able to afford it on both no problem.
This post was edited by Vids on Feb 10 2020 07:57am