Agree with you on the perception. As long as the fishing is in the classic bonefish style (wide open spaces). But I do feel - key word "feel" - that when in tight quarters I have much better success "stopping" bones with my nine versus my eight. I guess this comes in part from my experience dragging Snook out from under lighted docks in the Tampa Bay area. I have snapped eight weight rods at the butt section when pinching the line and dragging the snook out from under docks.
I take identical brand seven, eight, and nine weight rods with me when I head down to the Bahamas. The major factor that I use to pick which rod to use is not so much wind, but fly size and flat type.
I am leaning more and more towards size 2 flies (or larger) tied Key's style which tend to be heavier, and bulkier. The eight weight will throw these no problem on an open flat as long as the wind is not over 12 mph.
If I am fishing a spring tide up in the Mangroves (see North Riding Point GB) I will go to the nine weight with a sixteen pound leader and 20 pound tippet. These fish rarely burn over 50 yards of line because once hooked,they head straight for the nearest mangrove field. You have to boil them like a snook to prevent them from getting back into the groves'- in this situation I alway's use the nine weight because I feel the exra back bone is required to horse the fish (hey - it's not the classic style but it is productive on certain tides)and I can definitely tell the difference between the eight and nine.
I still end up fishing the eight weight seventy percent of the time. As long as the flat is open with little obstruction and, as long as I can maintain the right angles I whip a bonefish every bit as quickly with the eight as with a nine or even 10 weight.
If I am blessed, and find myself on an ultra thin flat with no wind I will throw lighter unweighted flies and the seven is perfect (o.k., o.k., this happened once out of eighteen day's last year in the Bahamas). Just set the drag and and let em' run.
Of course all of this talk on rods brings up another point in regards to Bonefishing:the reel. Although, I own three of the topline brand reels manufactured here in Florida, sometimes I wonder why. When Bonefishing I set it on the lightest drag setting - and never have I had to use the "train stopping" cork drag to reign in a bonefish. Of course the do look nice sitting in the display case in my office in between trips.
I appreciate the conversation on this board - It has me out of my mind with anticipation for my April 17th Bimini Trip!