Read about it in Trailerable lazy jacks
The $tingy Sailor
DIY trailerable sailboat restoration and improvement without throwing your budget overboard
DIY trailerable sailboat restoration and improvement without throwing your budget overboard
Read about it in Trailerable lazy jacks
The $tingy Sailor 
Have you thought of fitting a mainsail bag that the sail drops into, using the lazy jacks as support?
I did think about it before making the cover. But for a smaller sailboat, dry sailing, reefing, and performance reasons a sail pack would be more hassle than convenience. For how and where I sail, I’m very happy with the combination of lazy jacks and the cover.