I like it.
I did a one-sided rail system on stairs a while back. The original stairs were monstrous rocks and I built winding wood stair over them. I think they were around 4' wide. I put the rail on the inside of the curve, which is where the drop was. The other side was cushioned by an old be of ivy.
By not putting rail up on both sides, it was far easier to move furniture and appliances to the basement. The wide stairs made it easy to stay on track, going down the winding stairs.
Since I like to have 4,287 projects all going at once, so my house never looks done to the assessor I'm, also, doing another stairs with pavers, rebar (goes through bricks and into holes drilled to hold things in place) and it uses your gravel approach too.
In the end, works good, looks nice, lasts longer than a whatever candy bar used that line. . .
Good job [said by someone biased in your favor].