Thanks for all your inputs.
Arkansas stone is the way forward I think.
I have achieved a smooth finish on my jnat with a couple of scratches ,thanks to my tomo.
I have tried everything , including Shaptons ,up to a 30k ( I thought I finally had a use for it)
My DMT 320 is redundant . After spending lots of time running a screw driver shank up n down it I purchased an Atoma 1200, that's now my go to lapping plate.