That's the ideal approach to printing colored tees inkjess. Works great on simple spot colors, even some high end halftone prints. Get the black out of the way and concentrate on the next colors down (provided the art allows you to).
Artwork wise there is no need to spread the black. Butt register, white reversed out of the black. Black down first, flash then print your white then either print, flash print or single pass if your using a premium white ink. You may get by without flashing the black if it's on a high mesh. Either way, there is no need to glop down black on a low mesh in the first place.
For this to be successful (or any screen printing for that matter) your screen mesh has to be nice and tight. Hello crisp halftones and edges! A baggy screen, especially with the white second will look like crap. May have to make an off contact adjustment to suit your press or printing technique.
Black doesn't always have to print last. I wish that misconception would vanish from screen printing. It would eliminate some common printing headaches.