This is an idea I'm going to try out.
The key part is a Nobile stainless steel swivel which has a hole for a flagging line to pass through. I have drilled the hole out from 4mm to 6mm using cobalt drills and smoothed off the entrances to the hole.
The swivel worked OK for flagging to both front lines (although it wasn't that good at swivelling
), but to flag to one front line, you will have a line with connections going through the hole, so it needs to be bigger.
This is a Switch bar and at the top of the centrelines is a Slingshot Choad Ball. One front line connects to the top of the choad ball and the other connects to the white Slingshot Bungee Line through the choad ball.
The plan is to have a minimal sized replacement for a chickenloop below the bar. The front lines can be untwisted by twisting the top of the Nobile Swivel.
The Q/R is a Wichard.