It appears that in using one's own handwriting to design dobby drafts on a diagonal, it's not strictly necessary to write on a straight line. You just have to watch out for colliding ascenders and descenders, and then keep your fingers crossed. I took the text "The more things change, the more they stay the same," fiddled with it a little, and came up with the following:
First I've got to rewarp the loom, though. I really motored through that brown warp!
I'm also tweaking some of my Repper designs, and plugging them into a dishtowel template. These designs will both be interpreted in satin weave.