Our boat had a 6 footer and I think it was original when we purchased it. I order an 8 footer from GMI. The quality of the product was pretty good but the fit of the top is lousy. The middle 2 bows would not raise high enough to make a tight fit. I had to remove the bows from the sewn in pockets to get the bows high enough to make it taut/tight. I had to add additonal straps to support the center of the bimini. I recently add front and side isinglass panels.
I think a 6 footer would be a good fit. Our 8 footer works for us but we don't fish.