Ok well when I use Paterson/jobo reels, I don't have trouble sliding the film, I have trouble getting the film to simply go into the groves... Once it's in the groves it's no problem, it's that unlike the samigon. There's no tongue to lay the film on and guide it into the track. There's a TINY edge sticking out bit it takes me forever and a million tries to get both sides of the film to fall into the groves and not slip out of the other side.
Now I understand what you referred to.
By the way, Jobo too changed the design of their reels (transparent to white version) concerning those guides at the start of the groves.