Crop rotation part 2: Nightshades, alliums, beets and spinach and basil

So here are some issues to be grappled with to carry out my rotation scheme:

1.  Balance.  I usually want far more tomatoes and peppers and eggplant and such than I could fit in four little boxes.  But if I do more than four, then the following year I'll have an over-abundance of some other thing.  So will start my planning at four and see what happens - perhaps will do additional boxes of nightshades which then roll over to compost immediately instead of going on with the rotation?  Have also noticed that the soil level drops a lot after the first "composting" year, probably because so much of the bulk in the box was organic matter breaking down.  So... maybe do a couple extra boxes of nightshades, and at the end of the season, dig the dirt in them out to top off the remaining boxes, leaving a couple extra boxes for compost management and launch the following year?  Also worth noting that peppers often survive the winter in which case they might be "permanent" boxes instead of annual/rotation boxes. 

2.  Sorting out spring and fall.  Really in Houston one should be able to get both a spring and a fall crop of tomatoes.  So where is the room for beets and spinach?  I'm thinking that these things just get planted around the base of the tomato plant in the fall, along with onions since they're also cold-season growers.  And in spring, could do a very early spinach crop to be harvested in time for a late spring basil crop around the base of the plants.  So then there's the question about planting the same box spring and fall... which I think I'll try doing since the fall crop would be expected to be a pretty short one and hopefully can produce before the fungus takes over.

3.  Determinate versus indeterminate - I always wondered why one grows determinate varieties.  I mean, the idea is to have a steady supply of fresh veggies, not a whole slew at once, right?  But as I think about it, I realize that every year, I get only a short window of produce before it gets super hot and the indeterminates stop producing.  By fall they're so beat up and gross that I want to start fresh with new plants.  So if I planted determinates maybe I'd end up with more total tomatoes.  Clearly the thing to do is experiment.  So, I have planted both this fall:

Indeterminates along the fence, a variety called "Early Girl" which is supposed to mature in 50 days which ought to get me fruit before we get any freezing temperatures, and 

A nice experimental determinate vine, "Celebrity", on the patio which said 65 days to harvesting - again, it should be safe to get something harvested before there's a freeze.

Around these I will plant some onion sets and spinach and beet seeds.  Maybe intersperse the spinach and beet plants, assume that the spinach gets harvested as the beets get bigger?