Pretty sure the only difference with the Siren bar is the longer ropes on the trim straps. There's an extra couple of inches below the seat of the Recoil spring.
The bar is designed with a certain amount of throw - the IDS system lets you release the bar for nearly 100% "depower", so you don't need to throw the QR...
If you're riding around and need to hold the bar that far out, then you've got the wrong sized kite up or haven't trimmed properly. Good stance should see you with enough range of movement.
If the kite is at the zenith and pulling the bar to the stops, you probably got the wrong sized kite up.
There's nothing wrong with pulling down the black tube to reach the bar, if you've let it go... I do it all the time and I'm 6 foot too, and ride overpowered as often as possible.
PS lines are prestretched - they'll actually be shrinking