I did some runs up and down a section of Freeway at 0 (off), 2, 4, 6, and 8 and monitored the EGT, Boost, Water Temp and Fuel figures on my Scangauge.
Whilst it may vary significantly from vehicle to vehicle (I have 3 inch zorst, 33's and EGR is not yet blocked) I found that 6 to 8 seemed to be the best combination of driveability versus power and economy on my rig so I split the diff and it is set on 7.
Driveability will always be a subjective opinion tho and I will also be interested to see what effect blocking the EGR has...
Great point Vince... 8 was where I noticed the EGT and water temp start taking off as well
Craggit has an EGT gauge but for others... I also seriously recommend an EGT on a Chipped Engine (almost mandatory) as the EGT's can get pretty high pretty quick esp at low RPM's when the Chip is punching in more fuel than "factory"
Blocking the EGR dropped the EGT at least 50c and i am flat out getting to 500c where it was easy before. One mod i truly recommend. I have had no problems with boost spikes since doing it, highest being 16psi. Still going to put the Dawes valves on just for peace of mind.
So far on setting 5 i have seen no increase in EGTs or boost since putting the chip on. The power is a bit crisper over standard and drives nice, tows well too.