Most sunrooms even though they seem bright do not compare with real out in the open light preferred by the plants you mention. I would continue the light until planted in the garden. I never use 3 inch pots, preferring the 4 inch. Al

I think that it is not the same how much light there is in sunrooms in zone 9 and zone 6. Now, the light comes in a shallow angle in here whereas zone 9 California, the sun would be fairly high. When I measured the light level in sunroom and outside in front of it with my old photo light exposure meter using neutral 60% grey card (the standard) there was almost no difference at all because the sun beam light came straight in at 60 degree angle. But yes, you are right, I still give it that extra 3 hours of light. I will do an experiment, though. I have more snapdragons than I need and I have 2 plants that are almost identical in growth and seeds are from same packet. One will stay in sunroom and one will be moved for extra light. Just before I will transplant to final pot or ground I will take picture of them side by side. This way my curiosity will be satisfied. Gardening is so much fun!
Check the pictures on my blog that shows my sunroom setup. The post might be second from top or just click on Garden link at top.
Thank you very much for your input, I appreciate it very much.

Here is a link that might be useful: Seedlings update