the gm did a really good thing and gave us a surfeit of sample low grade mecha built around common archetypes (your gundam who's good in hand to hand and has vulcans in case it can't quite get there, a sniper, and a missile pod bearing fighter craft that can have legs as a treat). from there it was really easy to build a pc around a trainer and fewer learning curves in the test encounter.

by the time they let us fully interact with mech building, i just asked to upgrade my jet instead. my PC was already getting attached to it, I was already getting used to its idiosyncrasies (it's fast but hard to turn to a good heading; it has missiles and nothing else, but those missiles are fun to gamble on for massive damage), so it made more sense and felt so right