I use 400Tmax which I scan on a ColorGetter 3 Pro drum scanner. Optimum for me and my workflow is to develop somewhat less than I would for the darkroom. In Zone System terms, my "N" development time is about what a darkroom worker would call "N-1". In other words I shoot for a Zone VIII density of about 1.0.
Why? Less density means less graininess, which also means less light scatter due to Callier Effect, which means less highlight compression in the resulting scan file.
I suspect that the optimum density will depend on your scanner and software, so you'll have to experiment to find out what's optimum for you and your workflow.