Based on your observations sailing the barge, how do you think paddling the barge shape would be compared to a sharpie shape?

It is more dependent on the size and weight than on hull-shape. A slender light barge-proa would make a pretty good paddle-craft/canoe. I think it is important to keep the windage down, especially in the ends of the hull. The barge-shape has one major draw-back. The sides does not get any extra stiffness due to bending them to a stiffer shape, like the sides of the sharpie. The barge will always be more heavy then a sharpie or other shapes of the same size. Think of the barge more as a heavy work-boat/trawler/tugboat then a light bird playing in the winds.
A very light barge will have quick vertical accelerations, so if you want to paddle in more exposed waters, I would recommend a sharpie instead. If you are big and want to bring lots of heavy gears and stuff the barge will probably be a good alternative.

Cheers,
Johannes

I always recommend that you try a small cheap scale-model to test the concept before you commit to a large expensive build.
A barge-proa is way out there in uncharted waters, and you must be prepared to experiment a lot if you want something usefull.

Cheers,
Johannes

Big Len,

A barge does not have to be parallel vertical flat sided.
It could be somewhere half way between a barge and a sharpie. A narrow double bow ended scow, punt or pram.
If you still want vertical sides, make it wider in the middle.
Or you want to keep the bottom panel with parallel sides, flare the topsides.
Or do both ie, wider in the middle and flared topsides.
Any of the above will get you more side panel stiffness and more usable volume towards the middle where it is most useful.
Get it right and you should be able to reduce the negative tendencies of a barge more than the positive ones for your purposes.

Cheers

Rob

P.S.
And if you are going to make lots of models, make them all the same length and the same target displacement. Compare like with like.
If you are not going to radio control them or tow them behind a boat, use fishing line of the appropriate minimum strength and a good multiplying reel on a rod. Less drag and faster retrieval with no tangles. If you use a long beachcaster rod, you can tow the models from the bank.