John,
Be careful if you do decide to modify the rod itself as it may void the warranty if there is one. One way I have see to add a bit of weight to ballance the rod I have used is to get some of the nonstick grip wrap that tournament bass fisherman use. This is a strechy material that will grip to itself. right at the base of the cork make a wrap and 1/2 then lay some flat lead around this then over wrap that with more of the rod wrap works fine as long as you cast holding the hump of the cork. As stated above most of the time you will only have 10-15 feet of actual fly line out.

steve