I took your tweak and added it to mine. The result was a little quieter than the blade tweak alone, and overall much quieter that the plain whistle.
This is far from scientific, but I used a noise meter on my phone to measure the volume when playing an E5 and came up with the following values:
80 dB - plain whistle
76 dB - whistle with the matchstick tweak
73 dB - whistle with blade tweak
70 dB - whistle with blade and matchstick tweaks
I found that the whistle with both tweaks was a little more temperamental to play. Also, I took the blade tweak off to measure the volume and once I reinstalled it I wasn't able to use the matchstick tweak.