With the backlog being what it is, is it a good idea to reply to any new contributions? Even if you haven't reviewed their code yet. I've noticed from the few pieces I've looked at that there are a lot of basic errors that really slow down the whole process. So a standard reply asking for patience, if the opening post isn't strictly as procedure is a tiny bit about how it won't stop your application from being handled but will slow the whole thing down yada yada.
Something like this:
Hi! I haven't had a chance to look at your code, and it might be a while before anyone gets around to it.
I noticed your opening post isn't 'strictly' compliant with the procedure that's been thought up. It isn't a show stopper, but please make sure you thoroughly read Applying for permission to create full projects including coding standards and best practices. This ensures a quick resolution for when someone does review your code.
We really do welcome any new contributors, and ask for your patience during this process.
Best of luck!