For some reason, when I awoke this morning, my brain decided that was a good time to start problem solving how to use layers to create a convincing canvas interaction. All I wanted was to sleep for another hour… but no! - stupid brain wouldn’t let me!.. 
It also explained to me in vivid detail why I don’t like using patterns, and wanted me to pass on the information; But I’m not going to because it’s boring and now it’s late again and I don’t want to write another wall of text! 
But here’s some experimental layer effects I did this afternoon… 
^ This is the base layer - for toning the canvas with a wash.
^ Then the main paint layer for the impasto. The canvas texture always shows; I haven’t thought of a way around that yet (not sure if it’s possible) - but the texture is quite well hidden by a thick impasto effect. The thick strokes with show the canvas texture again if smoothed out.
I also discovered that layered impasto effects can be applied to the impasto brushes without looking harsh - I thought it would be overkill, but I’ll have to investigate further to see if it broadens what’s possible.
I thought all the tricks I was using would cause things to lag badly - but it remained really smooth regardless!
I was also just testing the spacing trick @Voronwe13 suggested and it seems to work really well! - I thought it would cause the spacing to become very obvious with faster strokes, but it doesn’t. I can’t actually understand what’s going on - I think the strokes look smoother, and perform better. What is this sorcery?! 