I have chosen to press the seams to the side so that I can stitch in the ditch where I decide it's needed when quilting (pressing seams open limit my options a bit later), but as a result, there are a few places were they are exceptionally bulky. I first hit the folded unit (right sides together) with a bit of steam and hot iron. Then I open the unit in order to press the seam to the side. When done pressing the seam to the side, I turn the unit over and take a little mallet to the place where those thick seams converge and I beat it down a bit. If I need to, I press the top where the bulk is just to heat it up a bit and hit it again with the mallet. Then I place the unit under a 12 1/2" square ruler and put a weight on it keep it flat and keep piling subsequent units under the same ruler. I leave them there at least until they cool down (or longer). It's what works for me and is a combination of what I've learned from Sally Collins' method and others.
I made a sample of Month 1 using this method and then quilted it on my domestic machine. I found that even though those bulky seams are still bulky, they are manageable as long as I use the proper presser foot to free-motion quilt over the seam. I am also lucky to have a sewing machine that lets me decrease the presser foot pressure and that is what I do when I approach a thick seam: stop, decrease the presser foot pressure, go over the thick seam, stop again, increase the presser foot pressure back to where it needs to be to have good quality stitches and keep going.
