beyond M1.2-1.3 it's all pretty academic anyway (though Brian Carroll did mention a M2.0 Lightning F6 shooting head on at a M2.0 target!) but the F1s and F2s, I mean with the short of legs they had you wouldn't need more than M1.7 anyway. In fact a missiled up Lightning I am not sure what sort of speed it could do I presume M2.0 is a reasonable maximum. So no Lightining would have been too restricted by the M1.7-1.8 limitation. But I really ought to let any Lightning pilot phrase this better. (PS I recall Porky Page in an article stating that he could never get to M2.0 in a Lightning (F6). Best he managed was M1.98 in an F6 though that was towards the end of the Lighting era in a beat up old F6 which is understandable).