Once the blemishes are sanded out and polished to a near clear shine Future acrylic floor polish will do the rest for you. It fills fine scratches, is self leveling and very forgiving.
I 'dip' canopies in and set on lint free cloth to 'wick' away drips. Then the canopy is covered to prevent dust from finding it as the dry time is several hours with 24 hours to cure. Window cleaner with ammonia removes Future if a mistake is found.
Many modelers fuss with spraying it on models for decal placement, it can be brushed on long as any bubbles are swiped off.
After using this product you will only need 1200 grit wet sand paper for modeling tasks.