attic flooring

Hello, I recently bought a house that has an attached barn. The area in the picture was historically used for storing hay, and we also want to use this area for storing hay. Around 500 20kg bales = 10,000kg. Green line: Top of an internal wall Blue lines: Top of an internal wall Purple lines...

Hi I'm looking to start to floor my attic for extra spacing. I've noticed that the house has a lot of bridges between each joist. The issue is a lot of them are higher. Some are a few mm, but others are 10-20cm above the joist. I've. Included a photo below. What is the best way to get round...