Yes I am OCD about jogs/joins in the rounds. When I did tubular knit flat for the first two rows (as it usually is) I thought I would have to figure out an elaborate way of wevaing in the tail at the start to hide the first two rows.
Turns out it's invisible (and I am incredibly fussy about such things).
Try looking at Eunny Jang's Endpaper Mitts on her blog, free pattern and the caston row gives a link to a page showing how to do the tubular caston and then tells you to do two rows flat then join into the round for ribbing.
Tubular castons look great, I love them and everyone who has seen them loves the stretchiness and the professional look.