The Timney is a great option.
Don’t sleep on Apex either. I’ve seen dramatic improvement in not only glocks, but S&W’s with it as well. Plus, there are many police departments all over the country that actually use the Apex system in their duty guns as they have proven extremely reliable.
As far as adding weight to the frame, you could always go the 3D print method and leave space in the grip similar to the X5 Legion.