The one and only time I did intarsia, I used Anne Berk’s method for doing it in the round, which makes a loop of the yarn you’ll need for a section before turning around. I like that it doesn’t stack the back and forth changes and it’s invisible because it’s happening where the color changes happen.
(The book had just come out and I couldn’t get my hands on a copy, so I was cobbling together the instructions. Having now watched the video, I don’t think I did it quite correctly. I never turned my work and went back the other way; I just made loops every round for the intarsia section. It worked out fine, though.)