2 car garage header size

[Kapry13]

Hi, I’m Kevin, a newbie to your forum. I. Hoping to get some insight on an upcoming project. My daughter’s 2 car garage is attached to her house on one eve side. It has two 9 ft doors with an approx. 2 foot wall between them.the total measurement is 24’ wide by 22 deep. There is no center header in place, and there is no storage capabilities either. There are a total of 3 - 2x3 that run the depth side of the garage, opposite direction of the roof line, and they have support boards attached to the 2x6 roof rafters. Appears very flimsy but has held up for 50 years. I would like to replace that with a center header and joists so that I could use for storage and provide more support. I want the header to span the length without support. SO...does anyone have a idea what size LVL I would need to run and which direction would it run, parallel with the ridge beam or opposite. My thought would be to run hangers and the joists off the header flush with the floor above the garage so that space would be continuous and open. Any thoughts about joist size would be great too. I will Probably plywood the floor and maybe Sheetrock the garage itself which is 2x4 construction. Thanks again Kevin