Answer: Well, for a rookie you're doing pretty well so far. Garening is always a learning experience.
It sounds like you may need to thin them out.
Thin them so they are an inch or so apart or, if you have enough, thin to just one per pot. Try to pick sturdy looking ones to save.
Each tomato plant is just one single stem, so you can use a small scissors or your finger nails to remove the excess by cutting them off short. This provides them space to get light and air and grow their leaves. Overcrowding can stunt the plants.
Once you have thinned them and they have recovered from that, you can transplant them outside as long as the weather is settled. They can be transplanted at a small size, that is no problem. Handle them gently and scoop the roots with some soil, replant immediately at the same depth or slightly deeper in the new container. Water well both before and after the transplanting.
Put several baby plants a few inches apart at the center of each bucket. Then in a week or so you can select the healthiest one of those to be "it" and remove the others. Your ultimate goal is to have just one good plant per bucket.
Four hours of full sun is a little less than they need, with six hours including noon being the minimum suggested amount. If you have cherry tomatoes, they may produce adequately on the reduced light. The main crop tomatoes however may only produce a little.
Make sure to keep them well watered so the soil stays moist but not soggy and fertilized regularly throughout the season.
Good luck with your tomatoes!
Q&A Library Searching Tips