I use the Stay-Flo starch in a 1 to 1 ratio. I bought a spray bottle of Niagra starch that was OK, but expensive. I kept the bottle to reuse for the Stay-Flo mixture, my reasoning was the Niagra spray bottle was designed for starch. It has not clogged once.
I starch heavy and I don't worry about bugs eating the starch since I don't store the starched fabrics. I figure by the time I'm done piecing a top, dragging it across the floor, running over the corners of it with my chair, general handling, and a Dachshund sitting on my lap while I pieced it, it needs a run through the washer after it is finished and quilted, so all the starch will come out in the wash. I don't make works of art so my system works for me. YMMV