These are illustration for the build.

The only downside of threaded stem, is that you have to cut them. For this I used a dremel with this setup + a nuts before the cut to redo the thread after.

To tight them, I am using 2 nuts: one that is static in the base, and a second to block rotation.

Using a handdrill, we can screw them through the whole structure, and then tight them back

As said, I made the model a bit taller, by printing an extension after having printed the parts at their original size
 

Adding the 20mm tube, That way it's easy to measure the exact length needed.

Detail on the inner filler, 

For the table: I used a cheap Ikea kitchen board. And choose to have  it in the upper left corner (as I am right handed). It's attached using a special foot that host the nuts.