I have both. I like the CC625 but have not towed with them. I think I have a side-by-side shot of the springs uninstalled. It's almost identical, just slightly shorter. Installed, it will give you back your stock ride height.
A lot of people choose springs based on the specs rather than application. You are correct in thinking that they will fit. They have the same "pocket" size as the 623s.
I know very little about towing. I think some members prefer a linear spring rate for that.