RE: Older race sails vs new designs
That's awesome that you're getting back into windsurfing. I think the sails that you have will be fine for starters and will match your smaller boards fairly well. I would use them hard until they break.
For the Hybrid, you should get a sail between 9.5 and 11.0 meters squared. Most people use 2-cam freerace sails for hybrid boards. Just make sure you have a big enough mast and boom for it. This big sail will probably be your most-often used since you live in an inland area.