Nice pictures Willy. It is in this ultra macro that a smaller imaging chip gives an advantage. The best I can do is like the picture below. But it is without stacking. You have to believe me but to avoid shaking I have to put the radio off .
Very interesting Chris ... you pushed me to try how far I can crop the original picture .. but you can easily see the disadvantage of a small sensor compared to APS-C or FF .. I should give this a try with my 105mm and de reversed 50mm .. I think (this is approx 3 sq mm)