@Anna N I'm very glad that you enjoyed the sweet potatoes. Kenji at Serious Eats does a great work explaining the science behind cooking and I do enjoy his writing a lot. I do however need to credit Harold McGee, it took me a long while, but I'm finally getting close to the end of On Food and Cooking. This book is full of interesting facts that can be utilized when cooking.
By the way, I'm obviously late, but I usually don't peel the sweet potatoes. I slice them and then place directly in the water. They float a little, but stay submerged. The key is the temrature, so it doesn't really matter. I think your description of their texture is spot on - tender and creamy yet intact.
