If it works for you,,, great.
High oil temps create high coolant temps.... other than killing engines of course.
I doubt you ever created propper duct work if you had negative results..
My own r and d indicates a different conclusion... Swapping from infront of the rad to the wheel arch resulted in a 6 deg (average) drop in coolant temp and about the same in oil temps.
The cooler was ducted in the wheel arch with a propper exhausting outlet.
A duct in the wheel arch will recieve clean air (not warmed and partially blocked by the intercooler) and will let the air pass through the core then out again much cleaner than if there is another flow restriction (the radiator) behind it... The ducting has to be designed and built correctly.
Ontop of that, without ducting the air is most likely to go around the cooler core than though it.
This is all apart from the fact the cooler core still poses a flow restriction and a above ambient heat scource to the radiator!
Cheers
Justin