At 1100 miles are you counting both new and replaced or repaired “wall”/fence? And is this pretty much all just single fencing, no or little double fencing with a road in between?
“are you counting both new and replaced or repaired “wall”/fence?”
Most places that need barrier, already have something, of some sort - even if it is just triple strand barbed wire for cattle. The new stuff is really no comparison to the old, So repair or replacement are not really significant considerations, to actually controlling traffic. They will put effective barrier where traffic is highest first, and those places will mostly be “replacement” (something that works, for something that doesn’t).
The big exception is about 150 miles in the Rio Grande Valley in South Texas, that does not have existing barrier. The hydrology of the shifting river, the hurricanes they get, and the water treaty with Mexico made engineering approval hard, and extensive private property claims also made it especially difficult - so it missed out on previous efforts.
I don’t really know how much will be double or single layer (double layer is mainly in the cities), but the barrier itself is a big upgrade, as is the dramatically improved surveillance built in with the new stuff.