Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Ah yes indeed! I've often wondered how to go about doing so? Is there a computer program to tweak the volume before installing it on the phone? Can the OP do that with a tone that is a stock tone?Also, following up on Mikestony's question, have you created a tone of your own using an app (e.g. Ringdroid?).
You often have to tweak the base volume on the source file in order to "make it match" the volume level on the built-in sounds. You'll also notice that even with the built-in notification sounds there is a very wide variation in perceptual volume for the same volume setting depending on which one you choose, and this is by intention. Perhaps choosing a different notification sound for messages could solve this issue.