Parallel channels and brush tool

Thank you for your support the other day. Thanks to you, I'm able to use it properly now.I have a request regarding the drawing function.

I would like parallel channels to be added. I would also like to be able to freely set the thickness of the brush tool and the transparency of the color. The current brush tool is too thin, making it difficult to see when analyzing waves.　 I would also like to be able to use markers.