I did a search and saw that these can be WS but I am unsure WHEN to start them.
I'm not sure what safflower is, but if it can be ws it can be done now -- it is winter after all.
In zone 6, you can do just about anything now. We haven't been getting too many long warm spells this year so early sprouting isn't likely to be a problem.
Until last year, I was zone 6b, and if I put in the zip from the village 3 miles from mine it still is. I'm in the tiny sliver of PA that changed to 7 when they redid the zones a year or so ago, but it doesn't really change our first/last frosts so it hasn't really affected what or how I plant.
When I do an internet search there is all kinds of info about studies on winter sowing it. But it is all commercial. Either way it seems to be ideal for winter sowing. The studies are for harvesting product. I just want it for ornamental and wild life.