>>265107989
>I jammed the plastic bit in the hole because the screw itself would not fit in the whole and said screw is the closest thing I found to "1/4-20" at Walmart
You're hurting me anon. Please don't bully that poor brass insert anymore. It's not made to be crossthreaded with drywall screws ;.; 
Stop whatever you're doing and go to a hardware store tomorrow, have someone there help you and say exactly this "I need a 1/4-20 pan head machine screw". 
Or better yet just bring your lighthouse in to the store find the most bearded looking dude working there and say you need help mounting it to your wall.