Regarding the 5 holes I'll be able to screw into above . The two of these near the top of the pad are lower. So I'll not be using them. I'll not need them anyway. The 3 around the center will hold the metal plate no easy.
I put a bit of paper over them to mark them out.
Next I lined up the template and marked on the metal where I need to drill.. I can't do drilling now as it's 9.30pm and a school/work night.
In this shot you can see the pool noodle. (Update: The pool noodle was terrible. Don't try it)
The back of this metal plate was thick with glue. Where the top pads were held on originally with two strips of tape, the bass drum pad add a rubber backing held on with copious amounts of contact adhesive.
Even though this bit is going to be screwed up against the backing, it was lumpy and horrible.
After 20 minutes of finger slicing fun..
Not beautiful but at least smooth enough now.
Finally, here is the K-Flex I bought today before I saw rhysT's post.
More in a few days when I can whip the drill out.
DIY is fun.