Here's my first picking (minus one for a "taste test") of the 9 Jochalos Yellow that I seeded just before Thanksgiving.
Orange Hat was planted 3 or 4 weeks later...
So, I cannot answer your question just yet.
I have 12 more varieties coming along that I planted in early January. I plan to collect and offer seed from all of them in the Fall Swaps. This late in the year, you could likely start some fast maturing regular tomatoes (eg. Early Girl) in a window sill or under lights, put them outside by late April, and have tomatoes by early May. I'm planning to start some myself this week. If you really want to start micro dwarf tomatoes this Spring, Heritage Seed Market, and/or Victory Seeds may still have some varieties left. Heritage Seed is where I got my latest 12 varieties. They were already selling out of some varieties by early January, though.