Thanks for your rapid answer.  It looks like I'm going to have to experiment,
but I'll wait until my current project is done and I'll try changing options
on-the-fly with a new project.

I notice some of the options are greyed out (ie. everything under the links
tab) while others are still accessible during a 'pause' (ie. everything under
the limits tab).

Can I use CANCEL and then update the project or is there still a bug with
Cancel? (Using version 3.44-1)