80 Series lift 2in or 4in - OME

Hi All, I have just installed OME springs and nitrochargers to my 80, i originally wanted a 3in lift, but i was convinced that a 2in would be better.
My vehicle has: FRONT - dual batteries, 1hdt engine, steel bar - no winch, endless air; REAR - Kamar rear bar, dual 33in wheels, 170L tank, cargo barrier and shelf.

The supplier selected 850 FRONT and 863 REAR spings for my vehicle, it now sits around 2in higher at rear and 1in higher at front without any fuel and vehicle completely empty. by just adding the two spares the vehicle drops 1in and sits even - i'm now worried that fully packed with roof rack, fuel etc it will sag in the rear.

I am thinking that with the same spring rate (i.e kg rating) and a '4in' lift the vehicle the 80 would sit around 3in higher than original. This would be my preference to bring the guards off the 33in tyres a bit. The other alternative is to install the 851 front and 864 rear springs which would reduce the sag.

I reckon i'd prefer the 4in option because the 2 in option would result in a much harder ride (especially when empty) and less articulation capability.

The supplier has led me to believe that the 4in lift would not be possible without installing a plate kit, extended brake lines and panhard bar extensions - could anyone who had done a 4in lift in an 80 series comment on what modifications they have needed?

I'm also interested in any comments for the 850/851 and 863/864 springs.

Thanks in anticipation, Twigiee.