Answers

Always seal first and then paint. Why are you re-sealing the corners? 

Seal the corners first, prime, and lastly paint.

I am not familiar with Chula Vista Roofing Pros, but I am familiar with West Coast Roofing, Alex. He is always accomadating and takes the time to ensure his team is always giving each job big or small the best service they can.  

Good afternoon-

An obscure vinyl slider would be an ideal option.