I have often tested panel-construction designs (plywood, aluminum, etc.) for fairness and ease of panel installation by making a cardboard model like the one shown above. I take a copy of the panel layout drawing and glue it to some stiff carboard such as Bristol board using spray-on glue. I then cut out the panels and bulkheads and tape them together with masking tape. Usually I don't care about exterior appearance, only whether the panels lay on properly, so the tape is fine. The one time I did care about the exterior - a planing hull that I wanted to see how the bow spray was deflected - I taped it together outside with low-tack automotive painter's masking tape first, then taped the interior seams, then removed the exterior tape. I painted thick carpenter's glue on all the exterior seams than painted the whole hull with housepaint. I ballasted it with sand in the bathtub until it floated on it's at-rest lines, attached a string bridle to the bulkhead just forward of midships with duct tape (the home hanyman's secret weapon), then took it down to the river for "tank testing". At a fast-moving channel in the river I used a float-type knotmeter to find a spot that was moving at the proper scale speed and sat the boat in there to observe the water flow past the hull. The hull lasted perfectly for the hour or so that I needed it to, and then slowly warped and twisted in the changing humidity over the next few weeks that it sat on top of my file cabinet.
Larger boats with bigger budgets for testing get properly tank-tested at the local university.
Hope for the best, but plan for the worst.