Alright, putting close range photography on the test out in the field. I have tested/concluded that with the macroadaptor 6.5 and the SK 72L I get perfect focus with a distance of 535mm from the front of the base of the lens. So, I have cut a piece of thin wood of this exact distance and bring with me in the field. Putting this piece of wood between the lens and the object makes my macro focusing incredibly accurate. I have yet to get a closeup out of focus. (ofcourse I have these 'woodguides' for all four lenses in combination with the 6.5 adaptor)
This image I used a sandbag to put the MAX on.