I know you prefer lemonade vs. lemonade flavor, but for what it's worth I had good success recently with these ratios of beer to Kool Aid lemonade mix added at priming sugar flameout.
1 gal = 1.375 teaspoons
2 gal = 2.75
3 gal = 4.125
4 gal = 5.5
5 gal = 6.875
In truth, I only did a 2-gal...