What do you guys think I should use for my jib?

Both my rails are pvc but if you can get your hands on cheap HDPE go for that. Check build a jib cult for stuff like this, all the answers you would ever need

pvc works almost aswell plus your jib will have rounded edges which is always nice also pvc is way cheaper, also its probably not worth the price for hdpe since pvc slides almost the same and last long enough too

Jib Cult is pretty dead now-a-days, but as someone who's made a lot of rails, pvc, metal, corrugated, etc. I try to help here in Ski Gabber. If you are pretty serious about making a jib, invest in HDPE, or Lexan. HDPE is what the mountains use, and that will get you experience wise, closest to feeling like your at a mountain, if that makes sense. But if you do use HDPE, make sure to use coping, pvc works, but I'd personally recomend angle iron,it works wonders.

Double barrel 1 1/2 inch on a 2x4 worked nice for me, triple barrel is sweet too. I have also seen people to HDPE in the middle with 1 pipe on either side of the piece of wood.