Softbox recommendations

[Teigas]

Hello

I got two elinchrom bx500w studio flashes, with two 17"x17" elinchrom softboxes on.
I am thinking about buying some larger softboxes. Any one got any tips what to buy? I see they have

Elinchrom
Rotalux Softbox 35.5 x 43" (90 x 109 cm)

and

Elinchrom Rotalux Softbox 35.5 x 43" (90 x 109 cm)

Or should i go even bigger?

[gdogg16]

If you can go bigger than 43" then do it. The elinchrom rotalux are awesome, beautiful light. Check out the photoflex boxes too. I shoot with the 50" wescott apollo all the time.
Edit: http://www.bhphotovideo.com/c/produc...e_Softbox.html

[azul]

Instead of soft boxes, you can look into a Photek Softlighter umbrella. Sort of like a poor man's Octabank.

[Teigas]

My room arent so large, so im not sure how large i can go. Do you use one or two? I see that i wrote some wrong information in my first post.

The question was Rotalux Softbox 39 x 39" (99 x 99 cm) or the Rotalux Softbox 35.5 x 43" (90 x 109 cm). Will they do? Or do i have to try to get somthing even bigger? If you have to choose between them ? wich one? or one of each?