Installing wiper arms W900...

I need to know during install, on the supporting arm (not the arm the wiper is connected to)..it has a 10-32 locknut.
Well, is that supposed to be cranked down snug or left somewhat loose??

I know the acorn nut on the main arm is tightened completely.

 

I wasnt sure of the threaded post the support arm sits on turns or if it was stationary.
If its stationary, I guess I need to make sure its loose enough to turn...

Geez....

 

KW sells these 2 ways.

Wiper Arm + Wiper = About $250 each
Wiper Arm alone = About $95 each

I was not able to find a generic one out there so I bought the bullet and got 2 new wiper arms, the cones and nuts and 2 blades.
Total was about $220.

You NEED new install cones...you'll never get the old ones out and they are only a few $.
(They are dissimilar metals and corrode very nicely INTO each other..)