I don't claim that I had all of my ratios right as it was pure "mad science" putting this together, but this is what I have scribbled in my notes when I brined and roasted a pork crown rib roast years ago. Results and crowd appeal for a group of 26 people (NEVER AGAIN!) for Christmas were very good. I will probably try it again and for a solid loin, I'd brine first and then inject. Just a suggestion, not a recommendation:
6 garlic cloves
½ sweet onion
1 C cider vinegar
½ C kosher salt
½ C sugar
½ t red pepper
1 C water
1 beer
4 C ice
2 sprigs rosemary
1 t dry ginger
1 t dry thyme
2 T honey
1 t dry mustard