It's a interesting technique, though I've been stuck in Montréal with little time and even fewer art supplies, so things have been difficult. I am coming to a two-fold realization about journaling and me.
1) I'm bad at it. I can blog like the best of them, I can "art" daily, but journaling does not come naturally to me. Keeping a diary was never easy for me either. I have to try to do it. Doodling? Please! Journaling? Less so. I've downloaded a pdf of 365 journal prompts that I'll flip through. I think I'll just scroll blindly to a page and choose one each day I need it and do it, regardless of the day indicated in the list. I already know what I'll do tomorrow.
2) As with ICAD, I find myself very slowly easing into the process as the days pass. I am less rigid, less stunted every day. I miss my paints and would rather use those (and I intend to from now on), but I find I can play with the pens a bit more than I could before. I gather the last 15 days will be the easiest for sure. JUst like with ICAD.
Also, distressingly, if I do a google search for Slow journaling images, my pages come up on the first page a images. I'm not a good example, Google, don't put mine so high in the results. It's a bad idea.