Here is my old setup. Note I did cut the top metal fan screen out and had to drill 2 mounting holes for the front screws to secure the fans to the RAD. You will also see that I had to mount the rear 120mm fan right next to the front for 2 reasons. First to allow for clearance under the mesh when the top plastic piece was clipped on. And second, to allow for the fan to mount on the rad. I also had to straighten the tabs on the top mesh to allow for clearance of the rear fan. it is only about 1/8" off, and is not noticeable.
Here you can see the slight bend in the top mesh:
Front of Rad mounted:
Back of Rad mounted:
I didnt have to cut the metal mesh on the top piece, just the plastic slats. I did however have to bend the mesh slightly upward. But it makes for a nice profile. And yes the fans are under the mesh:
To help with the clearance issues, I got a 220 Stealth Rad:
I used window seal ($1.49 a roll) to seal the rad and limit vibration from the fans: