My 1st ever head was 5mm higher and could notice just a few degrees lower temp, that is why I made these 5mm lower.
I have runned last season with the 1st lower version and so far no issues at al. Do they run better? I do not know. If they do provide a tiny bit more cooling you can go a tiny bit leaner on the tuning.....
Do the fins help as a kind of tail fin? maybe.... I am not of that caliber to notice, for me it is more a personality thing with the tiny advantages on the background. Also the straight up fins will give all the room for the airflow to bend off to the glowplug while with the normal fins and the higher placed bodies it is a bit difficult.

Soon one of the heads go to a guy who is able to notice the difference.