You can change the brushes, but it's not possible to have more than five in the toolset at one time. Although.... it's a great idea; I'll pass it along to the team.
Thank you. I really like the program and it can yield beautiful results but I find it tedious to use since, like all architects and most artists I don’t work sequentially from one tool to another. I need to quickly access 3 or 4 line weights and 4 or 5 felt tip colors and a few brushes. Even though it is easy to adjust the characteristics of the tool, doing the three or four steps each time you want to change color or line weight gets in the way of your thought process. It is helpful that you can change the tool type to suit your needs.
I find the tools them selves quite good with the exception that they don’t seem very sensitive to apple pencil pressure. As you make this app more useful please don’t loose the simplicity of it.
Thanks for these added details; knowing who (and how) people are using Sketch and Draw is invaluable.