RE: QQ New 73 In.
I was thinking about what I did and looked to make sure. I used the pieces ( not blocks ) drilled them and installed 4-40 bolts through "T-NUTS". Then hardened the wood with thin CA. I also added epoxy to the back side of the mounts where they came out of the plane. Worked for me all last summer and fall with nothing giving way or backing out. I still check all screws and bolts after a few flights just to be sure and all was tight!
Happy flying