If you want better temps and controll then only use sizable lump and not the shake from the bottom of the bag, it tends to choke. You may also want to blend it ( as mentioned above ) with some good charcoal.
I think that running with one hole and a valve at 225 is perfect and that's where mine runs al say long.
I only have three intakes too and it's perfect.
Slappin that bass like some delerious funky preist!!!
UDS, Half Pint (Mini UDS), Weber, ProQ 20, Kegrilla
*250 gallon cooker- 'The Meat Beast!!'*
British BBQ Championships
Grand Champion 2008
British BBQ Society - Southern Championship
Grand Champions 2009