Indeed useful background stuff for ATC to know, but isn't 'min clean' 'min clean'? When min clean goes up with s/b, so will your IAS? ATC have to put up with that and will probably not notice in reality. Just fly faster? Like a 'good chap' you are still complying with the request, are you not? In any case, ATC have NO IDEA what your min clean is. How many knots are you talking about? Would they really be significant? I doubt it would make any real difference.
The only real problem for a pilot would be if given an actual speed to fly, which would be unlikely at that altitude, but if given I would then have to 'unable' it to make the altitude restriction.