I recently used three different reels with different line weights on my new 7'9" for 4/5 rod. From the left - an Abel TR1 with a DT3F line, an Orvis mid arbor BBS II with a DT5F line, and a Lamson Radius 3.5 with a WF7F line.
I suppose that just standing there looking for a point where a given rod / reel / line combination "balanced", I would have come up with three different balance points. However, in the dynamic process of casting, I really don't remember thinking any of the three combinations was not balanced.
John
P.S. In deference to those who do not like full sized pics in posts, I'm using the thumbnail method. Don't count on it ever happening again.