what about that one:
Just take the theoretical quickest line around the track(easily detected as it is the dark line )and polish this line to adegree that rubber build up is reduced.Voila the best line offers reduced grip and will not gain much grip over the weekend .There will be a benefit from going of line especially in braking areas and out of the corner.
Maybe a possibility was to brush on some fuel or light oil to reduce griplevel just on the line.But I think polishing or closing th e surface so rubber buildup would be reduced could do the trick.
as we could see in bahrein the differenc with rubber down on the track translates to seconds to be gained,so if that did not happen on the line we could see more racing