If I can jump in with another question. I am considering putting in a
retaining wall as well and was wondering a few things. The retaining wall
will be in the back yard (Walkout basement) along the driveway going to the
shop. So basically the wall needs to hold the driveway in place, so what
type of wall would people recommend?

I was considering pouring a thick concrete wall. Any problems with that? How
can I make it as strong as possible?