Exlor
He could buy game shematics for 2 star mech. Make a trial one whit features similar to the one he want to make for real, and with the DP obtained improve his understanding before making the real one. Would have been practical (he gain experience on it too) and almost unexpensive... But it would have slow down the story progression.
Not sure if it has been mentioned b4... but are the mechs limited to the weapons they are bought with other than picking up someone elses weapon in the game? Does it means if i wan my mech not to carry a sword i have to buy a new variant??? The mechs dont have customizable loadouts??? Are loadout fixed?