Water/weather proofing cap/canopy

I recently found a color matched Leonard cap for my 02 extended cap. It sat outside for approx. a year so the tape on the bottom has dried up. Searching on here and the net I have read quite a bit of different methods for getting a water tight fit with varying degrees of success.
Has anybody recently went through this? What did you find worked the best?

Sealing tape?
Rubber gasket?
Silicone?

THANKS!

 

I just a few strips if foam sealing tape on the sides and front. Like to lengths on top of each other. And I sprayed it with a pressure washer and all has been dry.

 

Check this out too

http://www.bajataco.com/camper/camper_seal/index.htm

 

Bookmarked that whole site! I love it thanks!