Trey, I just finished redoing my 3 Vista windows on our '74 Sovereign
. If your VV's are the same as those in our '74 I can point you to a thread that will give you details on how to remove the inside Plexiglas and reseal the VV's. It's "Resurrecting Big Bertha... or, how I spent $30,000 on a $2000 trailer..." by Panama Red. Go to the Trailer forum, scroll down to Sovereign
then 1974 Sovereign
and click on it. Go to page #18 and click on the link included on this page. It will take you to pages with specific details on how to redo your VV's. I found it invaluable. Panama Red gives you a place in Canada where you can order the sealing material. It takes about 10 days to get it but the wait is worth it. I followed his instructions on how much to order and had enough to do my 3 VV's. The plastic trim INSIDE the trailer will give you a hard time but you can remove the Plexiglas inside pane with persistence. I found you will need the "fancy tool" Red invented to help pull out the Plexiglas. Also, if you are working in the heat, the butyl will be very sticky so be prepared. When installing the polyshim to the window frame I found it easier to remove the paper strip that it is shipped with and use household wax paper to keep it from sticking to your fingers and everything it touches. Keep in mind that this is on a '74 Sovereign so you may want to verify that '74 VV's are installed the same as in your '76.