I checked my plans from my Tele 40 that I built 15 years ago and the shear strips go on the back side of the front spars in the first 8 panels on each side. The strips go from top spar to bottom spar.
I have been flying me Tele 40 for all of these years and it is on its second OS 40 engine. I would recommend that you install the flaps, you will have a lot of fun with them. I can hover mine with about 1/2 flaps and a 10-15 mph wind. The only mishap that I have had with mine is I ripped the landing gear off of mine one time while I was practicing cross wind landings. I made mine a tail dragger and it ground looped on me when I did not get the up wind wing down.
You will enjoy flying your Telemaster 40, I still do and I have two 1/4 scale planes.

jeffeh