As long as your EC is low enough I'd move right into the DWC. The sooner the roots are in the environment they will be growing in for the duration.. the better.

--chris

Keep in mind that one reason that you wait is because of starting seedlings for soil in things where you can't see root development. So, you have to play it safe by assuming that if the true leaves are formed then the roots are formed. Obviously not relevant to your situation. Plus, the "true leaves" advice also comes from the idea that you aren't using a medium that stays together like a rockwool cube. In loose media you often have to use one of the leaves to gently pull the plant. It's always advised that you pull by a strong true leaf rather than a stem because you may rip a leaf without killing the seedling and even less likely if there are other leaves readily available, but you only get one shot with a stem. Using a firm medium will essentially eliminate the transplant shock concerns unless you let the roots get too long. So, yeah, I just gave a windier explanation that agrees that Chris is absolutely right.