i do something even more simple then that ... no drilling ..
I take off the xclamps and bend them a bit more (so there is way more pressure on the board).
reapply thermal paste and reinstall the coolers.
installation will be hard as they are tight as hell...
once done.. I lay little pads of gum (some people use glued togheter pennies but gum works great) to fit onder the memory on the underside of the motherboard and the metal casing.
reinstall the motherboard ... screw everything real tight (so there is a lot of pressure also on the memory on the bottomside)
then let it bake again. i disconnect all fans and let it warm up nicely.
let it overheat (3ROD wil become 2ROD (= overheat)) and then wait another 30~40 seconds.
then pull out the PSU out of the power socket. DO NOT MOVE YOUR 360!
Let it rest for about 15 ~ 25 minutes.
Turn it on .. will work perfectly for most 3ROD's (i mostly fixed 0020 with this..)
good luck