Just to avoid confusion- the 54 is actually the midi. The Deep Throat is a 39".
I've owned the DO (sold it about 3 months ago), and was using it with my Ranger Speed AS kit. The light was somewhere between a medium silver umbrella (with softer light, and the ability to feather) and a larger (50-ish SB). I was using it on a C-stand, with a grip arm, and in all honesty, regardless of which modifier you end up with, I would highly recommend the C-stand. Probably the best $180 I've ever spent on lighting equipment.
The Octa is actually an indirect light source, which means that the strobe head is pointed into the bank and away from the front of the box. It is considered to be the softest light modifier available, but I really have no experience with it.
Oh- and the Octa will need more than a C-stand:
http://www.bhphotovideo.com/c/product/546565-REG/Manfrotto_025BS_025BS_Super_Boom_with.html