Thunder,
I sold my Evo and was going to use the SitDrag/Harness combo for lightweight. Then when I saw the Kestrel, it looked like a great balance of size/weight/safety and it is so I sold my SitDrag. I don't need options for my harness
I have used it with SRT, One Stick, Aider, etc. You just have to wear it low enough that it stays under you (have you seen the "Falling Forward" threads?).
And for those that want a LIGHT safety harness, that Camp ALP Racer is the deal. weighs nothing. I used it with an XOP Climber seat/sit drag