To my experience, FR4 plates, O-Ring's on standoffs and tons of dampening material all mute your board very well. I have a NK65 Alum that I bring to work. I did the Keybored top mount mod and added o rings to all the existing screws. It has a FR4 plate, lavender linears in them, silicone case dampener and plate foam. It's a pretty quite setup, that still allows for you to hear the characteristics of the switch. But if you want a dead silent keyboard, then just opt-in to buying a silent switch. You may want to ISO mount your Mode board which I believe is the equivalent to the O-Ring mod (not gummy o-ring), go with a FR4 plate, allllll the dampening material and silent linears.