Yes I think the raised bed idea you mentioned could work well for tomatoes and peppers. The soil mix you described with compost and vermiculite should drain nicely. I have been using a similar blend for the past two seasons and the root development has been noticeably better. One thing to watch is the watering frequency in the first few weeks. If the bed sits in full afternoon sun the top inch can dry out fast especially when the plants are young. I usually add a thin layer of straw mulch after the seedlings are established and that helps hold moisture. Also consider spacing the plants a bit wider than the seed packet suggests to allow air circulation. That alone cut down on powdery mildew issues for me last summer. Let me know if you want help sourcing the lumber or hardware cloth for the bottom.

I checked the proofing times you asked about for the sourdough with the higher hydration. Stretching the bulk ferment to about five hours at room temperature gave me a more open crumb without the dough turning slack. I found that doing four coil folds at thirty-minute intervals during the first two hours helped strengthen the gluten network. After shaping I let the banneton sit at room temperature for another forty-five minutes before retarding overnight in the fridge. The oven spring was better when I preheated the Dutch oven for a full hour at 475. Scoring at a shallower angle also kept the ear from burning on the darker flour blend. If your kitchen runs warm you might shorten the bulk by thirty minutes and watch for the dough to feel pillowy rather than doubled exactly by volume.