Currently in the process of teaching myself to use substance designer and so far so good. The overall node based system is very similar to using the Unreal Material editor, the main difference is the name of the nodes from one program to another.
I created separate sub-sections for separate parts of the texture and used blend nodes similar to how I would use layers in photoshop.
I then took these separate sections and converted the grayscale outputs to a colour value. This gives me a lot of control when choosing colours and means I can create many variants quickly.
There are areas I wish I could improve such as the knots in the wood, they work and it's clear to see what they are however I wish they stood out more but overall I really like this material and the ability to scrape back the bark to see its underlying fibres will mean using this in Painter or in Engine will give me a lot of freedom to get the precise look I want.
Low Poly Tree using Substance Bark Material