Wood bed cross sill help

[novice]

I'm in the process of installing a wood bed and have run on a snag. The cross sills I ordered did not come with the plates that are on the bottom of them like shown in the LMC catalog. Does anyone know where to purchase them separate from the cross sills?

Also, Do the reinforcement strips attach to the chassis or only the wood?

Does anyone have the spacing of the cross sills and reinforcement strips front to back? The front two are obvious but the others are not.