Poplar, either aspen or tulip variety, is fine as a secondary wood. I'm not
sure what you mean by laminated here, but make sure you use freshly machined
wood, good adhesive, and clamp well (sandbags work on wide surfaces, as do flue
blocks and cement blocks and even bricks--set on rough boards to protect the
good surface--if you don't have a vacuum press, which most of us don't).

Laminated, gorilla-glued maple top to poplar bottom, like you thought with the
weight idea, great idea. And, what is the best glue for laminating?

Now getting that table top sawed properly....

Alex