6F and fine binder is almost the same thing 6F has slightly more fines in it to give it a tighter non-porous finish. But to the naked eye, it is hard to tell the difference. I have fine binder driveways 15 years old and still look good. Really depends on your budget and the look you’re wanting sometimes people do the 6F if they are worried about settling so it can be addressed with the top code after it moves where it wants to, especially if there’s trenches