I have just calculated the reduction in the moment of inertia (of the steered assembly) resulting from milling 225 grams out of the fork blade and it varies between 0.5% at full extension and 0.7% at full bump, which, I suggest, is so insignificant that it would not have a detectable effect on steering response nor the propensity of the Girdraulic fork to escalate steering wobbles into tank slappers.
Converting the front end to full Lightning specs will decrease the risk of tank slappers occurring. It will be recalled from my article that the standard Series C Girdraulic forks suffer a 32% reduction in the moment of inertia of the steered assembly when the fork extends from full compression (M of I = 21.3lb/ft^2) to full extension (M of I = 14.5lb/ft^2) and it is this reduction in M of I which can be instrumental in causing a tank-slapper. Not only are the actual values for Moment of Inertia of Lightning spec fork (i.e. no headlamp nor brackets, no speedo, shortened mudguard, only one stay, ribbed drums, alloy backplates, alloy rim etc) reduced (i.e. full compression M of I = 15.3lb/ft^2, full extension M of I = 11.3lb/ft^2), which will give lighter steering, but the relative reduction in value on extension from full bump to full extension is decreased by 6% to 26% . Most of this reduction comes from the reduced weight of the (alloy) rim.
I had not calculated the Moment of Inertia figures for the Lightning set-up when I wrote my article and this reduction therefore comes as a surprise to me. If I had seen these figures, I would have included fitting an alloy front rim as one of the ways to tame the Girdraulic fork.
Still, it didn't help John Surtees!