counter balance spring - Code 302-1

Single hung, double pane, aluminum frame. The counter balance looks like the picture on your 'swisco.com' opening page, just left of the lower picture. It is the one with the tube and red insert, the insert is 1/2"OD. No markings on the counter balance mechanism. A decal shows 'Code 302-1', 'Spec DH-81', 'Series 511, 520', 'Mst: 4'0" x 5'0" ', 'Conforms to ANSI/AAM 302.9'

I have several sizes of these windows needing the counter balance springs.

Thank you, Eddie

You are correct, the tube OD is 9/16".
I have two sizes 18" (need two rods, enough for one window) and 29" (need 18 rods, enough for 9 windows). All of them have a red plastic tip.
You have two tools to wind up the spiral rods for a preload, which one do you like best.
On the spiral rod at the red tip end there are two cross pins, which one is grabbed by the tool to adjust the preload, the one closest the end?
Are there any miscellaneous hardware items I should be ordering the I might find broken once I open it up?
Please provide me with the part #'s so I can order.
THANK YOU FOR YOUR HELP :)
eddie