I like your garden layout - I built simple overhead wire for a boxcab experiment years ago with copper wire and dowels, then made an aluminum jig with aluminum rivets set into it for a catenary soldering jig. Some success, but the dust gathered. The MTH system made me look, but I found it un-appealing. There's a catenary loop here with what looks like MTH components. The base fastening system is off-track it appears.
My plans are to follow the catenary systems built by the forum's Marty Fitzhenry and Don "ScaleRail", using Marklin HO catenary sections and home-manufactured poles. OGR magazine has Don's catenary article.