[MENTION=480142]Kars[/MENTION], switch to friction shifting (your shifters can do that) and modify a 9 speed HG cassette to fit on your UG freehub. You will find that friction shifting on HG sprockets to be smooth and easy. This is the simplest solution and you gain an extra gear.
My two cents is that 9 speed Ultegra would add weight (albeit an imperceptibly small amount).
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Bob
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