My tour frame maker was famous for that style. I said NO thanks. It's ugly as sin and makes the rear rack attachment lousy too.
I drew a full size plan of a harp shape frame and that's what he made. I actually wrapped the seat tube and made a BB/ frame pouch with CF.
It has proven to be indestructible in 5 crashes. LOL.
The fork had the wrong trail, so it was a fail. It didn't want to turn. Later I was glad it broke 2 times in Vietnam. LOL. It now has a tandem one to hold up my drum brake.
It has 70/ 70 angles, 46,5" wheelbase and huge chain stays of 19 3/4".
The tubes are solid as a rock. But it still shimmies bad when loaded, only if not holding the bars.