The boat info lists the hunter 90 but no sail deminsions. The brochure never had that info. Sailboat data had squat.
The 90 was built by JY Boats for Hunter but long out of business. However, call the forum store to see if they have a sail for that boat for sale as they should have the build parts for your boat.
If no help there, ask for Mike Thomas, Al Fooks or Joe Kerr who were former Hunter employees.
Don’t think Marlo-Hunter can help you. Former dealer