I dip in Future before painting, let it dry for at least a day, preferably 2. Then, mask and paint the canopy as you would normally do. When your done and the canopy is dry, dip in future again for a beautiful shine.
For step by step instructions go the follwing site:
http://www.aircraftresourcecenter.com/
Click on "tool n tips" at the top, then go to "Canopies & Masking", then go below and click on the link to "Amazing Canopies". I follow these instructions, for the most part, and they come out great.
Hope this helps