My calcuations for the mass driver

Here's why I'm asking all of these questions. Any feedback would be
welcome.

For the calculations I've been doing, involving a series of mass
drivers each accelerating a payload of uniform mass, I've calculated
their lengths and accelerations so that, following the other
assumptions of my scenario, they are firing in such a manner that
the energy produced from the solar field is drawn by the mass
drivers directly, therby avoiding the energy storage requirement.
There is no down time, where energy is being produced but not used.

I realize that I'm exceeding O'Neill's calculations quite a bit, but
hey, why not stretch it a bit, right.

My starting calculation is that accelerating 1 cubic foot of
material, with a mass of 173.9 lbs at 322 g acceleration a distance
of 4675 feet will require 374 MW for .95 of a second. Now, that's
just the energy required for accelerating the payload. I haven't yet
factored in the energy for the bucket, and the efficiency of the
entire system. Nor have I factored in the energy reclaimed by the
deceleration of the bucket.

Now, with sunlight producing 1400 watts/m2 and being able to convert
at 25% efficiency, a 500 MW output would require a surface area of a
circle with a radius of 674 meters (2212 ft)

I'm still trying to find information on the process of solar cell
manufacturing, and the density of solar cells.

I'm trying to satisfy my curiouity about how best to design a
bootstrapping operation and what the components sent to the moon
should include.

Anyways, the broad brush strokes for building a habitat as a
cylinder 20 miles long, 4 miles in diameter, with a shell 10 feet
thick, would require:

30 mass drivers, each launching 8 cubic feet per second (1,391 lbs)
for 11 years straight. No nighttime downtime.

Now this isn't including any material brought from NEA. Nor does it
include the mass required for the interior buildings.

Now to power this herculean undertaking would take 85.2 GW just to
accelerate the payload, (still haven't figured out the other parts,
as I've mentioned above). This energy could come from a solar field
of 8.8 km radius.

The volume of material would come from a pit 4.5 mile x 4.5 miles,
by 150 ft.

Anybody want to check my calculations - some feedback on the physics
would be nice, as I'm working in isolation here, just to satisfy my
own curiousity.