1) Supp or BA for lvling? I hear people say both but i have never played a bd before so whic is going to let me farm more efficiently and lvl.

2) Any good farming spots people would recommend at different lvls?

3) Best class to speed up lvling? Or am i better off solo?

4) Any guides on how to effectively use the class? I have never really paid attention to it much.

the fastest way to level is to take supp to 18 and the pump rest into bone army this allows you to have a healer out to keep u alive you run into a tough time doing this in your mid to late 20's but by the time you're 30 you should start rolling again

you could take supp to 50 but in the 40's supp starts to take a long time to kill and you chew through your power bar quick, but its safe leveling on oranges and reds

you could also take BA to 50 but you will have long down times between pulls medding your health but your dots will destroy oranges for sure

as for a leveling partner like any caster POM is fantastic and if your dou is a pac healer have him stun mobs when your dotting them