Something's not right here.
Were you grinding a lot of sinew and silver skin?
Shouldn't have clogged that easily.
I've put a lot of meat through my grinder and have never had it clog.
Did you have the blade installed correctly? (Flat side towards the plate?) I could see it having a hard time if it was backwards.
And after only 20 lbs. you shouldn't need new blades or plates.
You can easily sharpen the blades and flatten the plates when needed.
And you really shouldn't need to after only 20 lbs.
The reason for different plates is for different size grinds. and the plates really should last a very long time before they need replacement.
Now a #5 plate is a smaller size but that shouldn't effect the behavior of your grinder in the way you've described. It should only mean it will take you a few minutes longer to grind.
And if you do use your grinder to stuff sausage casings be sure to use a stuffing plate. It's essentially a plate with giant holes to let your sausage mixture pass easily without grinding it again.
Good luck on the shoulder but make sure your set up is correct.