A couple of A-body rookie questions.

So, go with a built reverse-pattern, manual-shift auto. You'll still be goin' through the gears one at a time. Back in the very early 70s, Had one in my original '69 340 Swinger with 4.89 gears and had to be in 3rd by the other side of the intersection in order to keep from chirping the tires with both the 1-2, and 2-3 shifts.
I plan on something similar in my 'new' '69 Dart when done, but maybe not quite so radical.