You’re going to need a strong umbrella swivel adapter as you get into off-camera lighting. This one from LumoPro is all metal and priced right around $22. You can also check out the Manfrotto 026 model. It’s about $13 more. I use both. Both are great.* The LumoPro has teeth on the swivel so it locks at an angle more securely when using heavy modifiers like the 50″ Big Mama Apollo softbox.
*Meg here. This reminded me of a Brian Regan stand-up bit. You gotta listen up to the 1:50 mark: