I decided to just go with the rice vinegar, but use it sparingly. My allergies do seem to be easing up a touch lately. (Some with my allergy syndrome do grow out of it when they're ... right around my age. Go go fortunate accidents of genetics and/or environment!)
So, my first home-built salad rolls, which I didn't take pictures of because they were quite ugly: steamed bok choy, some marinated tofu, a sprinkle of diced green onion (a nice touch), and some leftover rice. (Not rice noodles. Rice. I did find out why to not do this.)
I estimated some proportions for the sauce from a recipe found online: four parts macadamia-and-cashew nut butter (didn't have actual peanut butter on hand), two parts hoisin sauce, and one part each sesame oil, rice vinegar, and soy sauce (tamari), plus some water to thin it all out.
1) Use real peanut butter next time. The macashew was too subtle and fatty-tasting.
2) Try spinach. Bok choy, even when steamed, isn't readily bitten into pieces, and is rather more bitter than I wanted.
3) Use rice noodles, not rice. Every dip into sauce after the first one lost many rice grains into the dip.
4) Use two rice sheets, not one. Or else find thicker rice sheets that won't disintegrate during the meal.
I'll try this again in a few days, I think. The marinated tofu was good, though -- I used many of the same ingredients as the sauce, plus a bit of mirin and garlic. There's more marinating in the fridge right now, ready to be either rolled or just snacked on.