First - I said I would try to use a better grade than technical and that I recommend others do as well.
Second - It all depends on your required limit for insoluble particles. If they are sufficiently small enough and there are very few of them, then who cares? You can easily filter a solution through a 0.45 um glass fiber filter and what gets through would be of no consequence, as they would remain suspended in the solution.
Third - I'm still working on that one.
Fourth - OK - it's still extra work to make the gallon.
Fifth - Your're saying that if I weigh a gram of liguid it is more precise than weighing a gram of solid? Please explain. The precision of my balance or scale is still the same. And if I go your method, then I have to trust that I have truely made a saturated solution. If I weigh the dry chemical, then I KNOW that I have exactly what I wieghed. At least to the accuracy of my balance or scale.
You're having a lot of fun, but really, your system is a lot of work and based on assumptions and requires extra skill (to know that you have actually saturated the solution).