This has been really interesting to read- I’ve been growing purple sweet potatoes for years, but all from the local organic market (I think purple passion and this year also kotobuki). I pan roast them as fries all the time and the purples being more dry, crisp and caramelize beautifully.
Just throwing this out there for any other small backyard growers (I have an 8x4 sweets bed) - planting 1” slices of sweet potato directly in the ground works better. We do still make water slips because they’re fun for the family to watch, but the slips produce noticeably fewer and smaller potatoes than just directly planting 1” slices 5-6” deep- as one would imagine given that a potato can easily make 50 slips for me. So, if you’re not in need of 100+ plants, consider just slicing and planting.