I am about to start building my benchwork and my research has shown that we often over-build our bench.

I am going to use Fir as the frame with a 1/2" Birch plywood - all covered with 2" of foam. My layout goes around the room and will be 2' wide and have runs of 10 and 12 feet. I plan on using cross pieces every 16" inches.

So my question to those who may know: Could I use 1x3 Fir? It is almost half the cost of 1x4.