I prefer to use the liquid starch mostly for control of stiffness as well as overall cost.
I mix my starch 1:1 ratio. Yes I do get some flakes but I don't pay any mind to them because eventually they just flake off. Also, I always wash my quilts when I finish them so it doesn't really matter about the flakes anyway.
I use a garden spray bottle for application. I get the one with the spring in the sprayer head they seem to last longer and the mist can be adjusted easily.