I am also putting together the Jupiter. I have the tail and rudder glued on, the wing servos are in, and today i will be putting in the fuse. servos , and the tail wheel.
Your right, they show 2 tail mounted tail servos on the box.
This will be my second 4 stroker. I have one in a GP Escapade. I have the Magnum 52 in that one. Have you used ASP engines before. So far i am happy with the Magnum, but i am looking for an engine with a little bit more power, and not to expensive. Will check out the ASP. Good luck with your Jupiter.