I ran into some hurdles right off of the bat. First, I noticed they didn't quite explain how the the axes of the gimbal stay rooted in each ring of PVC. Also, I didn't want to bake PVC in ovens that I use for food. So I got to thinking and exploring and came up with the following solutions:
First, I used tee nuts to secure the axes to each ring; I bought mine at Lowes. Once I drilled a hole in the PVC, I pushed the tee nut through and used pliers to press and mold the base to the curvature of the PVC thus making it fit snugly. Likely I will secure the screws in the tee nuts with something like Loctite Threadlocker for piece of mind.
Second, instead of using PVC for the inner ring, I hot-glued the tee nuts to the bearing, then used a small amount of Instamorph to build a crude casing. It's definitely crude, but it's strong.
A note on working with Instamorph: In this case, I used small bits to slowly build up the casing. I also used the tip of the hot glue gun to melt together each layer. Meaning, I would lay down a new layer, then jam the hot tip into both layers and then smooth over both layers. I had to do this because the Instamorph cools quickly and successive layers wouldn't attach securely.
Using Instamorph and tee nuts made the inner ring a little wider than the tutorial. This meant I had to use a 1 1/4" coupling (instead of 1") for my middle ring. The last modification I made was to use a tee coupler. This way, I can put a handle on it.
Here's the final product and video