Doverseer, 
Arima: WebGL is always faster when hardware-accelerated, so I think the only case you'd get better performance is when Chrome is using SwiftShader and you switch to Canvas 2D.
In the next release I've added some code to try to detect SwiftShader and fall back to canvas2D if it's being used. This should hopefully resolve the problem, so there should be no need at all to build two versions of your project. However, since Chrome doesn't specifically reveal if SwiftShader is being used, I had to add some hacky detection based on OpenGL detections. It may have false positives and disable WebGL on hardware-accelerated systems, but then they will almost certainly have a hardware-accelerated canvas 2D, so performance will still be good. That's a better result than having some users get totally unusable performance, so we can live with that. Wait for the next build and let me know how things go.