Tapered tubes look cool but are far more difficult to work with than straight round tubes. A round tube can be clamped in a vice, and even a thin round tube can be inserted in a tube block and safely clamped. The tapered tubes require that a different part of the frame is clamped
I made some 5.2" risers with 15* backsweep for my jumper. This is the best that a 26" bike has ever manualed for me. My 24" does manuals very easily and now this DJ does as well. The Mobster 2.7" DH tire might be an influence, as it makes for a good counter balance... but while spinning the bike I can really feel the rotational weight. It'll get swapped for a Holy Roller soon.
Sean is building a dialed backyard set with a high offset 2nd