You need to have good technique. I have no idea what yours is like, but the higher SW is better suited to people who have been playing a long time and can serve and hit groundies with a loose arm. Meaning, the kinetic chain is being used properly. If this applies to you, then I'd suggest a racquet above 11 ounces with a higher, but comfortable SW to start.
It has taken me a long time to get back to hitting real relaxed on serve and groundies like I did as a kid.