After looking everywhere on here and doing a lot of measuring and research i can pretty confidently say that Renthal 971 bend RC are the closest to XTX 660 original bars.
Got some coming and will let you know how they fit. This is after my local garage fitted some from the fun bike section of Renthal after being sent the wrong ones by the supplier.
They really don't feel right at 735 mm wide and way too much sweep.

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only dead fish go with the flow..................