I measured the width of the weights in the order I wanted them to sit and added a little wiggle room.
The width of the center pieces is 17", giving the total width of 20" (1.5 inch pieces on sides).
The total length is 37". Each holds a 25kg, 20kg, 15kg, and 10kg bumper, 2 iron 45#, and assorted smaller plates at the end. Since I was running out of side space, I put a 2x6 under the bottom to allow it to sit partially on the platform, since that is also 1.5" tall.
