General

^ pretty much everything he said, BUT if you have lv 1 smoke then use it right after u kill the time sphere-- he might dispel/stun you the very first second he comes out.

Have fun!
And Pap is definitely do-able at Level 120.
For Pap I mostly do BS+SB the first body and BS+Assaulter the 2nd Body. BS+SB might get you hit a bit too much though in the beginning though so you might just wanna BS+Assaulter the first body.
Have Dark Flare on at all times, it's a free ~30k damage every time you get hit. When he dispels you ALWAYS recast Meso Guard first. ALWAYS.
If there are a lot of coins below Pap and Pap has dispelled your SP out, bomb Pap and then re-cast SP. This is because SP doesn't work with Meso Explosion.
When Pap goes into hiding mode go into Dark Sight to charge Assassinate, even at Level 1 a charged Assassinate does A LOT of damage, and the last hit is very very sexy, always try to hit the final hit of Assassinate unless you are very short in pots or you will die if you hit Pap.
And again have fun.