I know this is a real old thread but this gave me an idea that worked with my flossy nub nub shift knob.
-stock knob is 220.5 grams
-flossy nub nub shift knob is 346 grams
and sits about 1/2 lower
comes with nothing to secure the boot to the knob to I basically had to make a different/longer version of what dembflyr did.
almost the same except I also used a shift boot collar and the cap if the soda bottle.
I cut the entire top off with the cap (that has a small hole cut into the top of the cap) so I can twist the cap out to create an adjustable spacer.
a small hole in the cap so that u can twist it out or in to make sit lower higher on the shifter because it slants out wider as it goes lower.
then superglue once u get the perfect hight needed to push boot up to the bottom of the knob.
then glue on the soda cap and collar also I put a little electric tape for appearance
now push it through the boot then zip tie tight
reinstall back in car and around shifter
lastly a dab of blue loctite for me since my shift knob has engraving on top I wanted to be centered and level to read and screw on shifter until snug and again for me level writing
Anyway thats what i did at 2am cuz i cant sleep but I'm happy with it and I personally like this little weighted shift knob
customer service from flossy was a in a nice way sh*t along with it being the wrong threading (10x1.5), nothing a threading die can't take care of tho.