sub box for a 2008 silverado
 

hey guys im about to start building my sub box for my two alpine swr-t12 and im kinda looking for ideas on how think should the plexiglass or lexan windows be. also the cubic ft of air for one sub is anywhere from .4-.75 just wondering what will give me the best sound quality

I would use the higher volume recommended by manufacturer and plexi or lexan, not less than 1/2''