[dice]

One other thing: looking at that last picture
of the till-auger, shouldn't the auger bit
be on the other side, based on which way
the tiller is going to rotate if the bit hangs
up in the soil? (Look at where the
fuel tank and engine are if the tiller
frame starts to spin. If you have a
brace sunk into the soil beside it,
you don't want a spinning tiller to
mash the engine and fuel tank into
the brace.)

Edit: If the auger bit is on the other side,
the only way to rotate it so that it digs
into the soil is to run the driveshaft in
reverse (does it even have a reverse?),
and the engine and fuel tank would still
be "on top" or "in front" if the bit
hangs and starts to rotate the
tiller body.

If you can possibly bring yourself to do
without several feet of tomato bed
each year, you could plant an alfalfa
crop there that grows over the summer,
and a winter cover crop in September.
The alfalfa will root down deep into your
subsoil and leave organic matter behind
when the alfalfa dies, and worms will pull
some of the alfalfa top growth down in
the fall and some of the mowed cover crop
down the next spring and summer.

Then the next year move the fallow section
down the bed and do the same thing for
another part of it.

(I know this is asking a lot, leaving a space
that could have a tomato plant in it empty
for a summer. Maybe you could grow some
each year in containers on top of small stands
that allow the alfalfa to grow underneath them,
until you have rotated around through the whole
tomato bed.)