I'm more than happy to bow to greater wisdom. I'm deff not a mechanic, I'll have a go at most things myself the harder jobs usually end up me posting for help or a mechanic fixing my fix lol. I just think I know something or have read it somewhere and resort to searching other forums or google.
You can normally find something on SDIC, nasoic, iwsti or even scabbynet.
I will often be proved wrong or at least half right :D
Re the closed deck if no4 melted on the current deck, why not go closed deck just to be sure?