W650 seat on GPZ 550

Hey gurus! I haven’t seen this question asked anywhere so here it goes! I have a 1984 GPC 550 and I’m currently turning into a street tracker/brat style bike with a flat seat. I’ve modified a rear hoop onto my frame. Which would likely cause me to need a custom seat. I’ve been looking around to see if I can avoid making my own seat but I’m prepared to bite the bullet if necessary. One discovery I recently found is that the Kawasaki W650s Have a slight upward been in the frame similar to my gpz550. Does anyone know if the W650 cafe seats That I see so readily available, line up with the GPC 550 seat frame?

Here is a seat I am considering.

rover.ebay.com/rover/0/0/0?mpre=https%3A...2Fitm%2F183013857810


Here is a Few photos that help explain what I’m looking at. I know things won’t fit perfectly since my hoop is custom but both frames appear to have an upward bend in similar position near The middle of the frame. Are these bends identical?

Here is a photo of my current progress as well showing my stock seat and recently added hoop.

All the dimensions you need are right there in the diagram. Measure your frame and compare to the diagram to see if it will fit.