proper rack order for different meats in an upright masterbilt electric?

  I would do as Polishmeat said and you had in mind. You don't want raw pork juices dripping onto your formed bark and nearly done butt and brisket.

   Mike

Polish , welcome to our World. Really hopr you enjot it and  stay as a Bro. in Smoke (opps! or a Sister).

this may do what you need :

Any rack for these , you'll be placing the Butt and Brisky in first for sure ,so top. May save some heat when you put the ribs in and the Basting from the other will be fantastic.

Get a good reliable thermometer , place in meat to track "temperature of the Meat" and use a "guestamate" of 1.5hrs. of cooking @225*f / pound of meat. Again , only to track time as Briskys and Butts are notorious for long Stalls. Don't worry , be Patient . (Don't worry be happy -Bobby Farin in background).

When you place the ribs in ,here some reading :http://www.smokingmeatforums.com/t/126676/spare-ribs-with-3-2-1-method-and-baste

Have fun and as always. . .