Once you get your brace height to where the bow is shooting relatively quietly, then add some beaver balls to the string. Take off the flipper and work on shooting off the shelf, as suggested above. I place a small piece of rawhide string on the shelf and up the window about 1", then I cover with a thin piece of leather for the side plate, and use a slightly thicker piece of leather on the shelf. The 'ridge' under the shelf cover and the side plate make for a very small surface to come in contact with the arrow. You could use a 'rug' of some sort on the shelf.
If the bow still makes too much noise, you can then try going to heavier arrows.
With the above set ups, my bows all shoot very quietly (recurves, long bows, and self bows).
Best of luck, and welcome back! Arch