Ray, on the what appears to be a "short blade", " 5 inch blade doesn't really have any room to spare in length." make sure your tension lever on the upper arm is forward,,,, don't worry how I know this.... if that is the case, it is in the forward position, just unscrew the tension knob in the back until you have the room you need. Those are the only two things that can impact that, well unless you blade is broke and not 5",,, don't worry how I know this...
"I read on the website about the different sizes of holders and it said that the slots are visible to the eye as to which one is wider or narrower and that they mid size one started being marked with a divot let than 20 years ago." WHAT! That is news to me. I have to go look at the holders again. The width of the slot is not visible to this guys old eyes. I have never notices a "divot", humm, I have to check this out.