I was having a bash yesterday after I posted here and got a good result, with only 2 spotlightsThe Final Gather prepass comes before the SSS effect is calculated, so most of the SSS colours are left out of the indirect lighting on other objects. If you have saved the lightmap though (by rendering it with 'Writable' turned on and a filename supplied) and then render with 'Writable' turned off, Final Gather can already see the object in it's finished SSSy state, as if it were just a textured object.