Bit the bullet and bought 600EX-RT #3 and #4 to complement my ST E3 RT
Then I watched "Speedlites: The Power and Possibilities" Video by B&H
and was glad I did.
I am thinking of selling my strobes and batteries now.
I can't really make a case for any other lighting in the near future, I know I may lack some power but the portability is awesome.