Replace Kinco top sash guide

A handy person from North Port, Fl. says:
My top sash guides are breaking as they are 10 years old and plastic. I researched your site and found two possible replacements. The spring on one of my windows is 29 3 nm BSI. It looks like 18-166 is a match and 18-044 is real close. From what I can see, it looks like 18-044 is 1/8 of an inch shorter and the top is 3/16 of an inch wider. As 18-044 is cheaper, and I need 20, would it be possible and practical to substitue 18-044 for 18-166?

Your thoughts on this matter will be greatly appreciated.
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Paul from SWISCO responded:
Thank you for posting in our discussion board. We always recommend that customers replace their existing hardware with an exact match, or at least as close to exact as they can. The 1/8" and 3/16" differences you described might be just a bit too much. If the 18-166 matches your dimensions, then it would certainly be the better choice.
A quick learner from North Port, Fl. says:
Thanks for your answer and your promptness.
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