Mr. stevecham
It is not me to invent DF or plant it into your amplifier you already own. If your DF is achieved by feedback, it is the amplifier designer and maker's choice and not mine. This thread is not about modifying a given amplifier's DF to make you happy. All here have an Amp. with a given DF, whatever it is.
There is nothing wrong if a well designed amplifier has a high DF even if it is achieved by feedback. Feedback is not a bad word. Some excellent stuff out there is just made like that, to include the M1.
Whatever you like it or not, getting a cable by others experiences (more or less, whatever they might say) or by a listening judgment is so wrong. A speaker cable shall be tailored by the amplifier it is connected to, with calculated values and characteristics. Not empirical guess or a blind listening cession. Sorry if that is against your convention. See no issue for you to try it and hear it by yourself. For those who already did, it is a win-win situation.