Top Sash Guide

Hello,
As discussed by phone, please help me identify the correct Top Sash Guide as shown in 4 photos.

This is the window that we identified the correct balance is S351-18 option 1740.I now see that my Top Sash Guide (see attached photo) is unsymetrical (top tab longer in one side) and therefore the left and right parts would be slightly different. So there were many less choices in Top Sash Guides offered in pairs, and I now believe I have a positive ID based on measurements. I believe I will need Item 18-196.

So 2 final questions:
- based on the photo showing the unsymmetrical guide, would you tend to agree with my identification?
- when the website shows $ "each", that would be for the "pair", is that correct?

Thanks so much for your assistance. Attached is a photo of my balance and shoe, with integral pulleys.
This is a 18" balance #1740. Please provide information on cost and shipping time for 4 each custom balances as discussed.

I'll have to get you a picture later.
How much might a custom balance like this cost? How long to get delivered?

Additional photo as requested. How much would a custom balance cost? How long to ship once ordered?

Thanks,
I am not ready to order these yet because I will not be at the property with the windows until July, and want to see if the previous balanced I received will possibly work. So 3 questions:
- since the custom order email says the link will expire in 2 weeks, how do you recommend I preserve the custom order?
- once ordered, how long to receive the custom balances?
- if I want to order only 2, instead of 4, is that ok?

Thanks Ton