Umm, there's a good reason why people tell you that nothing can prepare you for Flanders' Pavé and that's because nothing can prepare you for Flanders' Pavé! Unless it's the 'real thing', anything else will only comfort you and lead you to believe it 'won't be that bad'.
But it will be that bad. And more so.
I used to find the stuff in Lancaster, Sedburgh and Dent okay, but I was variously told that the continental 'sets' were bigger (or smaller) so therefore smoother (or rougher), or that there's more (or less) camber on the continent, etc, etc depending on who the 'expert' was. So I gave up listening and thought I would just wait and see.
Well nothing could have prepared me for my first sight of the Arrenberg Forest section! You just have to convince yourself that it must be possible as people have done it before you! This 'act of faith' is the only preparation that's possible.
People talk about using more handlebar tape, etc, but my feet, hands and backside have never suffered. It's the rest of the body! I would recommend the best preparation is to be as lean as possible, to spend the first part of next winter on a serious 'core strength regime' in the gym, get some sticky 25c tyres and go for it. Finally if there is any downhill on the pavé (however slight) then think of some 'cross levers' for the brakes. It just gives you another hand option as swapping from tops to drops at speed on the cobbles is not easy (nor is speaking, seeing, thinking, breathing...)