Hi! Where do you get your furby spines? I need one for my boy but having trouble finding where to buy -_-;
The spines for Baguettella and Yuks are something called "flexible coolant pipe", pretty sure I just got it on amazon years ago, and they hold up great. They're a generic product but they're always blue and yellow, they fit together just the same as acrylic teddy bear spines (the white spine material you may have seen other customizers using) and are usually much cheaper, compare prices though!
I recently obtained some of the dedicated acrylic spines and I can confirm they are stronger (as in they hold a pose better, neither product will break), but for a lightweight project like Baguettella the cheap version was more than fine. Heavier projects, like ones actually supporting real furbys, multiple arms, etc. will bend under their own weight and won't support as many free-standing poses with the cheaper material, but it's up to you whether or not that's important.
One thing that's true for both materials though: they are extremely hard to connect and disconnect. This means you won't have to worry about your projects snapping while assembled, but it does make the process of actually assembling the spine to be the appropriate length in the first place very difficult. I highly recommend having 2 pairs of wrenches/large pliers to break the pieces apart, and having a vice or something else to keep the spine steady while you put your weight on it to put the pieces together. Good luck!