Hi Andrew;
I put one of these Laminova exchangers from Mocal in my plane.
Very compact but still a few pounds, but it seems to work well so far.
I used to see better oil cooling in climb than water cooling, but in cruise I had better water cooling than oil cooling.
This was likely from my old, good looking oil cooler scoop, which I don't think was very efficient. I've cut that off and changed it to more of a P51 style scoop. Still looks ok, but it should work much better, so when I return to flight I'll not be able to say definitively if any improvements are due to the Laminova cooler or the improved airflow. However, so far in static ground tests my H2O/Oil temps are quite close.
Todd waiting for the smoke to clear