I got out the books and spent a couple of hours reading. Nobody talks about batt technique at all. So I guess that means, wing it. Ok, good to go. I have winged it before and not failed utterly and like most times, common sense and reason will get me through this. So long as the batts are the same thickness all over, it will be fine. If it looks lumpy, spread it out or remove it. Butt the edges or do a slight overlap where it seems to need it.
I have read in several of my books, that it might be wise to put quilting lines on the fabric before the sandwich is made. If this were a simple quilting pattern and it was all done on block edges like the quilts made when I was little, I wouldn't worry about it. But it is rather more complex.
There is a lot of quilting to do on the plain white squares and its going to be important that the stitch patterns are reasonably squared to the rest of the blocks. It's a lot of work but this is what happens when you fall in love and just purchase a thing without really thinking it through. I fell in love with the look of this and so it remains. Thankfully, the hard part of the sewing is done. All those curves.
The quilt borders have to be sewn on and a decision must be made about binding. Will the binding be attached to the top or will the binding be done after all the quilting is completed?
There are some pretty significant tasks to do before I get to the sandwich but I will get there.