I never could find the timing belts.
I think the only option is to get a belt gauge and a bag of misc belts and measure. The other two belts are available at hi-fi stores and used in reel to reels. I don't have the numbers for those though. I wrote it down and lost the papers. I put this project on the back burner for a long while. If you ever find a supplier for the timing belt please let me know.