Why can't you mod the advance/retard, is it all sealed where the vacuum unit goes into ?
There will be a way of restricting the total advance, or even letting it have more.
As I do them I get the idle/low running nice, then set about limiting the advance by way of the stops, even making some if necessary to restrict the movement of the weights, tweaking downwards until all the pinking has gone, then I add the vac can(adavance) afterwards, if this proves too much advance on cruise conditions I use a old A series vac can that is adjustable and tweak that, after making it fit.
tabetha