Dry-Fit like a Glove
The dry-fitting of the cabinet into the base structural piece represents the first test point for construction precision. Thankfully, everything worked out with the assistance of some minor sanding.
The fit was so tight that final assembly of the "finished" pieces will require heavy clamping-- that should be a nerve-wracking experience.
On a side note, the strength of the base structural piece was confirmed after separating the two pieces when the base structural MDF component fell off the three foot table. My heart stopped for a moment; however, upon investigation, there was no damage to the piece. Solid!

