since no one with a 265 has chimed in yet.
i don't think you "need" any shims as the general radar beam angle is about 12.5 degrees up and down of horizontal plane. however, i like them and put a 4 degree wedge on my 232 and now my 330. i used seaview mounts with the wedge between the mount and the hardtop. mount is located on the hardtop "hump". i get very good returns, no issues. ron