Replacing my 40 year old window spline

A handy person from Tarrytown, NY says:
The spline that I am trying to replace is 40 years old and oxidized and probably shrunken but the dimensions are:

The new dimension (5/16) is 9/32 on the old spline and the old spline is
7/32 thick. The old spline looks about the same as the picture of the 59-061 spline. Should I buy the 59-061 or is there one that is closer
to the old.

Thanks, Jim
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Paul from SWISCO responded:
Jim, this is actually a more difficult scenario than it may seem. You would really have to try the spline out in your frame to see if it fits- I can't think of any other way.
A handy person from Tarrytown, NY says:
Hi Paul,
I think that part #59-061 or #59-067 will do the job.
A handy person from Tarrytown, NY 10591 says:
I would like to try some splines, however SWISCO
doesn't give me any choice other than buying several 10 foot lengths and trying them. It seems to me that the thickness of the spline is the critical dimension and SWISCO doesn't give that
dimension on many of their splines. I don't know where to start. I should be able to send someone a piece of my old shrunken spline and get a recommendation.
Profile picture of Mike
Mike from SWISCO responded:
Good morning, Jim.

You can give me the part numbers of any spline of which you'd like to receive more measurements, and I'd be glad to get the information for you.
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