Generally speaking, Miscanthus does not require cold stratification in order to germinate. You can sow it now, either in starters, or directly, and, if the seeds are viable, you should get germination in a couple of weeks.

How long to maturity? ~3 years.

True to parent? Unlikely. You may get the dwarf stature, but the odds are against variegation.

Thx Donn,
Looks like it's another year to get the needed height from castor beans.....Karen