sweet and sour sauce

I'm craving sweet and sour sauce, and this isn't a rare occurrence. I found several recipes that I plan to smoosh together. After much trial and addition (didn't scrap it at all), here's what I came up with:

2 tbs green onion (the white part), chopped
1/4 c white vinegar
3/4 of a green bell pepper, chopped
2 tbs tomato paste
1/2 c water
1 tbs garlic-ginger paste
3 tbs brown sugar (packed)
1 tsp granulated
1/2 c soy sauce
2 tbs lemon juice

This went far enough to cover chicken and faux abelone-seitan and rice for five people. It took a while of adding things for it to come out good and strong, so it ended up with a slightly smoky flavor. Ideally, I'd rather not overcook it, and I would use pineapple juice instead of lemon.

For the chicken and seitan, I chopped them into bite-size pieces and dipped them in beaten egg and then in flour, then fried them in just enough oil to cover the bottom of the cast-iron pan.