The sticky place they've put me in this, is there's only 6 slots and both offense and speed require sets of 4 for their bonus.
I'm leaning toward offense/speed as secondaries since realistically a 10% speed bump on 100 is only a +10 which can be achieved through secondaries on the right mods.
Health or defense mods with primary health percentage increase seem to be the right road I think for my experiment.
This should be interesting. Thank you by the way, to everyone and their valid input. It's nice to have a productive thread.