RE: Sig Somethin Extra
Mounting the canopy is not too difficult (I just finished SE #2, Irvine 53, maiden this weekend weather permitting)
Carefully cut the canopy to size along the guidelines and it should fit neatly to the fuselage top cover. Use canopy glue to stick it to the sloping former at the back, then run a thin line of glue along where the canopy meets the cover. Masking tape will hold it in place until the glue dries.
Did mine this way and it seems pretty secure. (Canopy is still in place on SE #11, pity about rest of the fuse!)
regards
Terry