B4 with AE shocks does not really need changing, it was always the case that I just ask Mick Cragg what he was running, I can't drive or setup a 2WD car for toffee
with regard to the thin/small combo packing up, basically because of the smaller holes, the oil has to flow faster through these holes, the faster the flow of oil the more turbulant and less efficient at 'getting through' the holes the oil becomes.
thats why, at high speed movement of the piston, the small/light combo has more resistance than the 'matching' big/thick combo