For clarity, I would point out that for 35mm, I use SS reels without clips, and they work fine. The ones I use have a little "C" shaped wire frame - you push the film into the "C" and it crimps slightly, which is enough to hold it in the reel.
I've seen the Kindermann reels with the spike. In fact, I remember selling them when they were new, current stock

. I don't recall, however, whether they were available for 120, or just for 35mm.
As for aprons, I have original Kodak aprons that work fine. The problem with the aprons is that they don't work well in inversion tanks. There is a problem with how the chemistry flows around and through the apron. If you use the Kodak tanks you are unable to use inversion agitation and you use a lot of chemistry.
I can load 120 on to SS reels without using the clips, but if I use rotation agitation, about half the time the film starts walking itself out of the reel.
In a perfect world, the SS 120 reels would have a latchable clip that one could latch open, insert the film, and then release the latch so it would hold.
Alternatively, the SS 120 reels could have a gate at the outside end that one could close, preventing the film from working it's way out.
In the meantime, I use the plastic AP clone reels in Patterson tanks for 120, and SS reels in SS tanks for 35mm. The plastic reels cause problems sometimes, and require too much chemistry, but I can make do

.