Venturi air adjustmentHey Chopper, you shouldn't have any problems getting it to temp. That's what's great about gassers. I've used mine at -30*F and wasn't running it on high burner to get 225* chamber temps. Mine is the small one at 14" deep x 16" wide.
As far as the burner gas inlet, if there is a disc that rotates, that would be for the air/fuel mixture in the venturi. I would set it at close to full open for moderate to high altitude, around 1/3 to 1/2 closed for lower altitude (this compensates for oxygen content in the air).
If the burner fails to light after several attemps, then close the venturi for a richer mixture and try to light it again.
When you light the burner, take note of the flame color...it should be blue, with about 10-15% of the top of the flame being an orange color. That will give a fairly clean and hot flame, with a little bit of resistance to wind flame-outs. If the flame is all blue, they can blow out more readily. To get less blue flame just close the venturi a little more.
Hope this helps you out. Good luck. Jump back on if need more help, I'll be in and out all day and most of the night here.