36.1mm (1.42 inches) from top of mounting plate to bottom of shaft.
If anyone does this please make sure to bend the LS-33 1.6mm thick metal mounting plate using tools (hammer, vise, etc) to the shape of the NG controller top, don't expect the 4 bolts in the top plastic to do this for you. They will not and you will crack the top case of the NG controller. The 4 bolts are there to secure it in place, not to bend the metal. Also the 4 bolts don''t need to be incredibility tight to securely hold the LS-33 stick in place. A little more than finger tight is all you need.
Its best to form the mounting plate while its removed from the stick so you don't damage anything.
The dust cover is on the top of the NG controller vs. stock stick having it below due to the height issues.
I checked the other Seimitsu sticks and the LS-33 has the shortest shaft depth under the mounting plate.