I disdain handrails that are wobbling. Give me something sturdy, giving confidence. That doesn't mean rubber-covered wire railings (most common on sailboats) nor rinky-dinky metal railings of many "trawlers." Maybe it's just me with less than average balance.
Last month transiting the decks of two diesel-electric locomotives while underway on the Alaskan Railroad, appreciated the iron-solid feel of their handrails!
I'm thinking of spanning the gap between our Albin-25's bow pulpit and the wooden handrails atop the pilot house with a pair of SS rails extending forward horizontally from above the pilot house windscreen, then bending downward to anchor points atop the front of the house. Bending low to grip the existing wooden rails atop the cabin is awkward.
Making a PVC model is a good idea. You could clamp PVC or wood stanchions to the existing rail's mounting points.
Perhaps your new rail could extend, continuously aft along the side or top edge of the house. I don't have the sense of how high the new rail wants to be, or how low the side deck is behind the sheer.
When shopping for our trawler, we eliminated some lovely boats that had narrow side decks and poor handrails.