Hmmm, today's (or any day's) enforcement persons (who might pull you over), might just ask you to show them dim, and then bright (or, bright, and then dim)?
On my setup, the dims are on individually, and on high beam, both filaments are lit (via individual high and low beam circuits). No problem with legality. Unlike the aftermarket "not legal for on-road use" lights that so many people use nowadays.