The more than 5 natural arches in the Black Hills

This weekend, my friend Chris and I continued our search to find the natural arches in the Black Hills and found two additional arches. Off Playhouse Road near the intersection with iron mountain road, there is an unmarked Custer State Park road at about 43.82357, -103.4005, that is the nearest point to two natural arches.
The first we saw from the trail but have not inspected closer because our goal was a bigger arch.

The arch we sought to find is a named arch several miles south of playhouse road and about the same distance East of Center Lake. I will not give the coordinates because spotting the arches is part of the fun. EDIT: As a hint, a run of power lines is close by the arch.

Thus, we have personally confirmed 5 features exist in the Hills. Multiple sources confirm an arch in Calico canyon. I believe the following links are each referencing that arch: here, here, and here. Another source references an arch on Grand Canyon Road in Wyoming. Another source gives estimated GPS coordinates of an arch off Iron Mountain Road. Yet another source has a picture of an arch not referenced by any other source. The Natural Arch and Bridge Society has an arch listed in Harding County.
I thought research had led me to a feature called Fairy Window at Sylvan Lake, but this appears to be a suspended boulder. See here and here. On that note, I don't recall if the entrance to Chopping Block at Rushmore is a hanging boulder or a bridge.
Apart from the Hills, there may be two bridges in the badlands. See here and here.
The conclusion from our total confirmed count of five arches, along with the fairly clear documentation of other arches, is that there are easily more than five in the Hills. This site appears to be easily disproven. Now the question is whether there are 9, 12, or more? We have uncovered evidence of a likely 10 in the Hills if Slim Buttes in Harding County is considered the northern most reaches of the Hills.