A worthy contest! Legionic could you post the top 3 ships of each week in your OP or another thread? I would really like to see the winners!
Though the part requirements seem overly complicated and the weapons have very different power and crew requirements.
I think the easiest way would be to make it a money limitation. You could make several brackets for people with different time constraints:
Cruiser (Default, ~250k credits)
Battleship (Intermidiate, ~550k credits)
Dreadnought (Champion, 1200k or even 3000k credits)
This way you donΒ΄t have to count the parts as you see the total worth of your craft with one look.
World Limiting tonnage would penalise using armor unduly in your proposal as itΒ΄s three times as heavy.