Hello Jim,
I turn Persimmon frequently and Sweetgum on occasion. Sweetgum grows like a weed in my neck of the woods, but I get my Persimmon out of North Carolina. I usually turn bowls from Persimmon, but I also do small projects as well. I particularly like the black banded Persimmon for the best color. If the tree was large enough, you may be able to get solid black bands large enough for a pen out of the centre heartwood. These black bands are very hard and look like high polished ebony when finished. Really nice timber to work![
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Sweetgum can be colorful, but it generally looks better if it's spalted. Tone spraying can help the color if you have the equipment and you know how to do that... I would opt to stabilize the Sweetgum if possible for increased durability of the barrels. Fresh cut Sweetgum is better than aged cut, as the colors tend to get muddy with time. Good luck and best wishes to you in all of your woodturning endeavors!