Think Twice, and Finish Once
I know, there is more then one way of doing things in finishing, but it seems to me like you do somethings that are creating your own problems. I see this in some of your post.
If you don't have the "right" materials on hand, you will try using almost anything you do have on hand. This "give it a try" attitude always leads to problems, as I am sure you know yourself.
Learning by trial and error can be very costly in the long run, lucking out once in a while, may not work the next time. Being over anxious to get the work completed, and not allowing the materials to dry properly causes more finishing problems then the finishing materials.
Whenever your in doubt, ask first for an answer, not after you have the problems.
I mention this because I see your really trying to improve your finishing, chemicals can be very complexed, because they vary from one manufacturer to another. That's, why is best to stay with time tested products that work for you.
One of the keys to finishing, which I still do myself, is to first make up complete start to finish sample panels. One, it will tell me if all my the materials are compatible with each other, two, it will allow me to learn the right finishing process, and three it gives me a change to make corrections on the samples, and not on my customers pieces.