Hi Jim,
I went through this dilema when I built my motor. I first removed the old baffle and ground material away and made a new baffle and reattached it by drilling some new holes and using self tapping screws. This worked but I was nervous about the screws. Even though I used loc-tite I thought if one came loose it would destroy the motor.
So I finally decided to make a small cover out of sheet metal and weld it to the bottom of the oil-fill tube. The oil-filltube is steel so it will work. One problem I ran into was I already hade painted the valve covers (base coat/clear coat) so welding may ruin the paint. I was able to use a mig welder with and make small short spot welds. After each weld I used the rags soaked in water to cool the cover to prevent hurting my paint job. Also, the metal on the bottom of the oil-fill tube is thin so only short spot weld will work or you will blow through the metal. I was able to get this to work sucessfully even with new paint on the cover. I smoothed the welds out with a die grinder after I was done.
Here is a pic of the completed baffle. You can still see the holes I drilled.
Good luck.
https://home.comcast.net/~perkin50/DSC01341.JPG
My car.
https://home.comcast.net/~perkin50/index.html