Jersey,
I'm not an expert, but I can tell you what I did, with good results. I went to the local Aircraft Components and Equipment store, otherwise known as ACE Hardware, and bought a variety of foam weather stripping products. Various widths and thicknesses. Then returned to the hangar and installed the weatherstripping anywhere there was a gap between the canopy and the airframe. I left the stripping I didn't use at all unopened in the bags and ACE was kind enough to let me return it.
In addition to the gaps around the canopy, I found that a lot of air was coming in through the wing spar openings in the side skins. I pulled the wings partially out and applied weatherstripping around the openings, just tight enough to stop the air. Worked like a charm.
With the above measures to keep the cold air out, and my baffle plates to partially cover the oil cooler and radiator so as to raise the temperature of the coolant and direct all the warm air into the cockpit rather than dumping it overboard, I can make the cockpit as warm as I want, even in the coldest of Adirondack winter days.
A tip - clean the areas where you want the weatherstripping to stick thoroughly with alcohol to promote good adhesion.
Hope this helps.
John