Good luck with your experiment, I tried spraying out some grass from some alfalfa, guess it will be a few days yet to see if I had any luck.
I used Agro _Culture Liquid fertilizer on some other hay land, and Phos nitrogen blend. It's been so cold and dry the hay hasn't been growing.
I couldn't really see from the label on your growth regulator what it is, Never used anything like it as around here drought usually regulates any growth.lol