Hi Tim, I can see that perspex would help that issue. I never have an issue with wax moth. They are present all the time between the perspex & wooden frame of my observation hive. All they do is consume the hive ‘sweepings’, for want of a better word. They will never be an issue in a healthy hive.
I’m a fan of a sold floor that is the same level from front to rear. That way the bees take the debris ‘sweepings’ out the entrance & drop it onto the ground. I believe that a solid floor with no ventilation apart from the entrance is the most efficient way to keep bees. Coupled with a hive that is kept reasonably cool outside on hot days.