All we have to do is choose a different "useless ability" for each engine size.
I made SW engines of the same sizes of B5 engines (at least the same sizes of fission engienes) so they could use the same abilities.
I also made different sizes of shields, so we may need to add them other "useless abilities"
Take a look at these pics:
http://se4kdy.cyberwars.com/temp/sw_pics.zip