Ancient dragon wood cannon (yama hbg) (two pellet jewels)
Conga cap Z (evade dist +1 jewel, evade +1 jewel) Conga vest Z ( Evade jewel x2) Narga Guards X (Evade jewel x2) Narga Coat X (evade dist+1 and evade +1 jewels) Narga leggings X (two free slots)
Gives you evade+2 Evade distance up PelletS/Scatter Bow up
Or you could go pure Narga X (Helm not cap), swap in Butterfly/Obituary pants, get those skills, better defense, and a more consistent appearance. Set can pull quadruple duty as well since the shot skill is gemmed in from scratch; you can use any of the three shot boosters or AutoReload without needing a separate armor set for each.
Don't get hit and hit it until it dies, in that order. Kill it, carve it, wear it, repeat it.
Yeah, I always broke Diablos' horns without even trying to, using pellets.
Evade +2 and Evade Inc is not really necessary to fight Diablos (but I would say is very necessary to pellet Kirin). But then I always use LBG on him, so I always used HGE with Pellet up, which is why I was never able to use evade skills when I needed to farm him.
I tried it later just to see how it was but I still prefer my HGE LBG Pellet Up gear over it.
Leveling up jobs is a means to an end. It isn't content.