Well, if you have played the mission before, you already have some of the old rewards go straight for the Sub Zeros.
If you play it with a new toon, pick the scaling rewards first (Freeze ray, grenades and BO... skip the snow tubers, unless you want a bunch of cryotribbles). When you get freshly promoted, then run the series a second time and get the set. No point in doing it on level 10 for example. As the deflector is obsolete after the first two missions with the new rank (It won't count toward teh set anymore if you get the other set pieces after promotion)