Personally I keep it at 160-175C (320-347F) because I don't want to be even close to combustion.
Are you running the fan during pre-heat? (I run it on lowest)
After that, I also let the material pre-heat (no fan, capped) as well for at least 5mins. (Also some stuff like inital pulls of air at start of pre-heat and stirring after pre-heat, but I have no idea if that does much)
From what I've heard (and seen a few times), heating to a higher temp and then stepping it down might give you more clouds. But I assume that is either just an effect similar to condensation and/or maybe slightly more extraction due to better heat soak.
For reference I just have an EQ with nothing special, and my material was free (not the best/freshest, though I assume that's more about weak flavor or quick-to-turn-harsh more than it is potency itself) and also I just rip a bit by hand instead of pre-grind (I keep the AVB, doesn't taste bad IMO because lower temp).