Building a rack for my balls! Could use some advice.

[Rickys_Reptiles]

I'm planning on building two adult racks. The main issue that I'm having is that the legs/supports on the side are not going to be long enough as the rack will be 72" tall and the boards are only 48" long.

I'm thinking of combining some of the boards to extend the leg/support length. I think if I do the chemical welds and screw the legs to the rack, it should be durable enough to move. But, I don't really have any technical knowledge.

If the supports on the side are too short I'd do this. Double them up, stagger the joints.