If you're new or returnee like me. With 6000 orb, you can get SR weapon brick to MLB all four servant shark. And feed all pluses into them.
I say 40% assault/defender on all element is worth it in the long run.
A little late for that.. already MLB'd it with the copies.. will try to remember to do that for futuer rainbow assault weapons... I combined two of my diablopteruxes to put it in...