Top Sash Guide part identification

A quick learner from Ladera Ranch, California says:
Dear Swisco,

Thank you for the terrific website and helpful videos. Could you please help me find the Top Sash guide part in the attached pictures and dimensions?

I think I've located the correct channel balancers for my two non-tilt sashes that have been giving me problems. The one that seems to best fit with the dimensions I measured is: 28" Series 385 Channel Balance, Product Code: S385-28 with option 2720 for a 19 lbs sash. I assume when I order the Option 2720 the spring strength includes the calculation of 2 identical channel balances on each side (1/2 the force on each balancer to add up to the weight of the sash).

Thank you for your help.

Sincerely,
Dennis
User submitted photo of their window hardware.
Profile picture of Paul
Paul from SWISCO responded:
Thanks for posting, Dennis. This looks like our 18-171 top sash guide. This is the new style used for Alpine windows. However, you will likely need to cut off some of the top so that it fits your sash.
A quick learner from Ladera Ranch, California says:
Thanks Paul for the quick reply! I reviewed the drawing details and the 18-171 looks like it will work after I trim the top part a little just like you said. I ordered a couple today and will let you know how it turns out! Thanks again!

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