I can load ss 135 or 120 reels 3/4 drunk, half asleep with both eyes closed while listening to music and thinking about sex. Just takes a bit of practice.
Been using 35mm and 120 SS reels since the late 1970's. Usually, the only time I have ever had a problem is when:
1 - the reel has a very slight bend from being dropped or banged.
2 - I don't have the film centered well and get a crimp / bend at some point, which makes it very hard to recover from when using SS reels (if that happens I just start over from the other end of the film).