8 of us are traveling to Spain in September 2019. We had a fabulous private guide last year in France and would love to find someone like him. Any suggestions?

Is this for all of Spain, or do you have somewhere in particular in mind? Someone familiar with all of the countries difference provinces will be difficult to find. We normally use guides familiar with the local area. You will not be doing yourself a favor using a guide from Barcelona to visit Sevilla or Bilbao.

Check out Historian, Stephen Drake Jones, of The Wellington Society, based in Madrid. Interesting person and great tours.

Rick Steves https://www.ricksteves.com/tours/spain-portugal But it may not be so private as you want.
the official tourist website of Spain.
https://www.spain.info/en_US/activid...cuitos-espana/
https://magicalspain.com/
Looking at those prices private tours will be very costly.

Call these folks:

Exclusive Food, Wine & Cultural Tours

that is Robert's website.

There are several people active on the Spain forum who own travel-related businesses. I cannot think of anyone who has been more generous with advice about Spain over the course of many years than Robert/Maribel. That is the reason that I feel comfortable in mentioning them although I do not use an agent to oversee my travels to the country. I have an advantage of speaking near-fluent Spanish and being familiar with many if not most regions of the country. If I wanted to have someone plan a tour of the country, I would look to them first.

Will attest to Robert/Maribel's generous advice - I would take any tour with them in charge!