Thanks for the "great" comment, I actually made that about 10 years ago, long before Brining was popular.
Thirdeye, you've posted some good stuff, we'll have to talk some on brining.
Osmosis, is how brines work. Reduce the salt and it will take longer. Is there a minimum? Probably not.
What will change is "time".
The standard brine is 1 cup salt, 1 cup suger to 1 gallon. I think most times reference that formula.
When people change the salt, they don't realize the ratio changes and because of how it works, it WILL take longer to achieve penetration. How much. Just too many variables to try to give you an answer.
My best suggestion is to test it for yourself. If you reduce the salt, keep the time the same and see if you think it's what you want. If not, brine it longer.
Larger cuts take longer, that's why I do my Turkey's 2 days, because of the mass.
TQ is a cure, first and foremost so it will "cure" the meat and change the color. A lot of the original brines had TQ in there for food safety, (I even mention that in 101) but I take it out if you keep the brine cold.
Author Brining 101