Great write up man, NO 6x9 will fit because they are very shallow speakers, and there is not much clearance behind them, What I am doing is making mdf spacer rings and putting 5 1/4 inch speakers in there place. Also the 6x9's are only in the bose model I believe I will be sure to take measurements when I do this for future installs. Also for an alternative to your putty spreader you can sue a butter knife wrapped in electrical tape or this.
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