Sub tool setting changes aren't retained when I switch to a different sub tool.
Settings changes can be preserved by unlocking the sub tool.
Steps
You can unlock it by pressing the lock icon next to the stroke view on the Tool Property palette.
Note:
If the sub tool is locked, a lock icon will also appear in the tool name on the Sub Tool palette.
If the sub tool is locked, a lock icon will also appear in the tool name on the Sub Tool palette.