I also own Photflex softboxes and do not have a pin-hole problem. This is not normal. How new are the boxes? If this is a problem with new or relatively new equipment I would contact the company. I have had good luck with their customer service. I had a speed ring break and they replaced it immediately.
As for the rotation, I don't have the problem at all - even with my extra large box. I am using Novatrons and the speed ring clamps down quite tightly. Again, I would contact the company and report the problem to see what they say.
Finally, the holder for the reflector is a pain but does work. With 42 inch reflectors, however, I have to brace the standard lightstand as it will fall over otherwise. I suspect that if I used my heavy lightstand it would be fine.
The shot below was done with my Photoflexs.
Hope this helps.