Actually the best way to get a good crust on sourdough is to use a Dutch oven preheated at 500 degrees. I tried it last weekend and the difference was night and day. The steam gets trapped inside which helps the bread rise properly. You want to score the top at a slight angle about a quarter inch deep. Let it cool for at least an hour before slicing otherwise the inside will be gummy. I have been using a blend of bread flour and whole wheat about 80/20 and it gives a nice texture without being too dense. The starter needs to be fed at least 12 hours before you mix the dough. If it is not bubbly and doubled in size the bread will not have much rise. Next time I will send you my exact measurements because I have been tweaking the hydration level.

I also tried adding a bit of rye flour to the mix and it gave a really nice depth of flavor without being overpowering. The key is to keep the dough temperature around 78 degrees during bulk fermentation. I use a proofing box but a microwave with a cup of hot water works just as well.

One more thing make sure you are using filtered water if your tap water is heavily chlorinated. That can kill the yeast activity and leave you with a flat loaf. Let me know how yours turns out.

The tomatoes need at least 8 hours of direct sun so if your balcony only gets morning light they might struggle. I had the same issue last year and switched to cherry varieties which did much better with partial shade. You should also look into getting a self-watering container because inconsistent watering causes blossom end rot. Mulching with straw helps keep the soil temperature steady. I would recommend starting with determinate varieties since they stay more compact and do not need as much staking. The soil mix I use is equal parts compost perlite and coconut coir. Fertilize every two weeks with a balanced liquid feed once the flowers appear. Prune the suckers when they are small to keep air flow going through the plant.

I also found that adding a layer of crushed eggshells around the base helps with calcium which prevents blossom end rot. You just rinse them and bake at 350 for about 10 minutes then crush them up. Another thing is to water at the base rather than overhead to keep the leaves dry and reduce the chance of fungal issues. If you see any yellowing leaves near the bottom remove them so the plant puts energy into the fruit instead. The variety I grew last season called Sun Gold was incredibly sweet and produced well into October. Let me know what kind of space you are working with and I can help pick the best varieties for you.