As someone who spent months trying to do anything and everything to improve the break I can only say what has worked for me because what works for me may not work for everyone.
I could never manage to really spread the balls with so much control until I made these adjustments on my break shot:
1.) Short controlled back-stroke.
2.) Choking up (around 10-12 inches from the butt)
I began using a shorter back-stroke after watching Joe Tucker's videos on breaking. He found that very many pros never really get their power from a big long back-stroke like you see from most people. It instantly changed my break. I went on youtube and sure enough, the best breakers never reached out way back to get their power. I started watching the people at my pool hall and again, almost all of the best breakers had a short back stroke that never went far back at all.
An very knowledgeable instructor once told me that choking up could help my break. I tried it at first, hated it. I felt it was way too high and very unnecessary. Especially around 10 inches. Months down the line I was playing 8 ball and tried it again, this time with a shorter, controlled back stroke. I got down, lined up, pulled back about 4-6 inches and let go. The cue ball made a loud crack as it hit the rack and popped up a few inches into the air and rolled back to center table. Balls scattered everywhere. Choking up still felt very weird, but it's something I am getting more comfortable with.
Before these adjustments I was never able to break this well with so much control and with so little effort. I was honestly shocked at the outcome and how much of an impact those adjustments made on my break. This allowed me to forget about trying to blast the cue ball and focus on my mechanics. Tip placement, Staying in line, making a full hit on the headball etc.
Hope this helps