My two heavy 2x4 top benches were built similar and wish I had thought of the 1" doweling, I like the idea a lot. I bought a special bottoming bit for my router and built a special fixture to level the 2x4 stacked glued top. I am a machinist and used my 1.5" end mill bit to cut the mortises then squared them with a sharp wood chisel for the table base assembly. With lots of glue and long lag screws the table was finally assembled.