Iv found its quite random whether he spwans alot or not...
I use to think it was to do with which location he spawns at, i.e. if he's temple he doesnt spawn much, but if he's out in the open, like above the Takla text then he spwans alot...
but recently im not so sure. I was at the temple last night, i had zerk, so i thought ideal i'll go right in and Ghost spear everything... but when i got there i saw high lvls all over the floor, and lots of giants.... shortly after i went in and started to hit eveything he spawned again... and then again just a minute later.... needless to say i died once... but had never seen him spwan that much at that location before..... maybe its just if he's in a bad mood
