[MlMt] How to set default "from" account?

[Dave C]

I’ve got several individual accounts at different mail service 
providers. My goal is to avoid clicking Send without first selecting the 
correct From account.

In M|M I set up a bogus account (at a non-existent domain, and not 
enabled in M|M) and I’d like to make this the default so as to force 
me to choose before sending.

Is this possible? Or suggest an alternative method you are using?

Thanks,
Dave
M|M noob