I just went thru this with my -7 after 220 hours. Cracked along the bend of the baffle that attaches to the cooler mount on the left (vertical) edge and also at the right side of the cooler mount in the little "box" that lines up the baffle line at the rear of the assembly.
The problem is that the assembly from the centerline of the engine to the outboard edge of the oil cooler is long and unsupported, and the weight of the cooler flexes the whole baffle assembly fore and aft during operation, eventually cracking the corners where the flex happens.
My fix was a 1/8" thick angle of 6061 at the bend and a newly built baffle plate (the one that surrounds #4 valve cover). A doubler at the small crack on the inboard side. Than I added a diagonal brace from the inside of the top valve cover bolt to the inboard top bolt of the oil cooler.
In the end, the angle is so much stronger than the surround assembly (baffles and mount) that the material used seems unimportant. Yes, 4 ounces added but as I read elsewhere ... it's strong enough now to pull the plane out of the hangar using the oil cooler as a handle!
We'll see. That's why they call it "experimental" !!
Cheers