The way I read the rule, it won't be legal if you have an adjustable valve. If your brake fluid reservoir is above all your slave cylinders, then you should not have a proble as long as you keep your rear mechanical brake shoe adjusters properly set. The inline residual valve is supposed to counteract the spring from substantially pulling the shoe off the drum. So your brakes are there right when you step on them. This can cause excess drag. Adjust your brakes often, here's how I do it with two people:
One person sits in the car, which is on jackstands, and files her nails.
Take off the rear wheels
Have her press the brake and hold it
Put two lug nuts on snug to hold the drums in place
Thighten the adjusting star wheels through the holes in the back of the brake plate
You can only move the wheel so far each time you pry on it through the hole...call each pry a "movement"
Once the adjuster is tight, back it off 4 movements
Now your helper can let off the brake. The rear end should roll without brake drag and should stop without much brake pedal travel. If you have any drag, you either have a bent axle or runout in the brake drum.
