Hi, welcome. Go slow, its easy to try and do it all at once when new. We have all been there. Observation is key, especially early on. Learn what your plants are telling you, keeping them happy, healthy and alive is all about observation. This thread may have some useful information for you. As for your ??s, some general feedback, not Redwood specific per se.
- Have a few options. The roots will dictate the size of the pot once you see and work them the first time. You are likely to need a repot or two before a more “final” container.
- Coming from a nursery container you will be the most aggressive in root reduction, it has likely been in that container for years.
- Rule of thumb is one major move at a time. Because you shouldn’t repot until early 2023 you have time now to do some cleanup and pruning, potential wiring prior to the repot as your tree will have time to grow and recover between now and then.
- Generally repot is while the tree is dormant, but temps are warming up and the trees are starting to awake. Not dead winter. Not post spring flush. That is what makes it such a scramble. In Texas that is late Feb./early March and a snap freeze can be a death nail to a freshly repotted tree. In SoCal your weather is less volatile. MIRAI is an amazing community, but a local club with members that have local knowledge on species, weather, and timing of work is an invaluable tool as well.
There are a lot of folks here from SoCal. Reach out. “Join a local club” is still the best advice I have gotten in bonsai.
Good luck!
Bonsai On!!