One other thing. Your plywood is cut wrong. The grain should run top to bottom not front to back. And it's not just cosmetic. Although plywood has multiple plys it is stronger in one direction. That direction happens to be with the grain, just like solid wood. As has been said: Glue is your best friend.
BTW if you had used 3/4" plywood and proper joinery the 1 x 4s would not have been need for anything except trim and you wouldn't have needed a single screw.
You're putting a 29 in front. And a sump inside. How will you access the sump?
Recedite, plebes! Gero rem imperialem.
Quote me as saying I was misquoted.
Once you get rid of integrity the rest is a piece of cake.
Here's to our wives and sweethearts - may they never meet.
If you agreed with me we'd both be right.