BTW ther are a few fender options that might help with venting for the oil cooler but may still help keep at least some mud off of it here is one:
There are also these scoops, not sure if they direct it to your specific cooler location, but they might, or you could make a similar concept:
For your more street based riding a super moto fender is a little less drag and less lift on the front and cuts down on that twitchy feel of a dirt bike front fender, this one is vented at the rear as well:
The vents have flat areas that catch some of the upflinging mud while letting air straigh thru, might be good for you.
Again LOVE the build and bike.