Fitting saddles to kayak

I just bought a set of Rola kayak saddles for my roof rack. How do I position them at the optimal width to decrease Hull deformation when strapping down my kayak? I have a WS Tsunami 125 Kayak.

2 conditions for best result. First, if possible, adjust roof bars to be positioned under kayak’s internal bulkheads. Second set the saddles to provide maximum contact to hull.

  1. don’t use ratchet straps, 2. set the saddles so the boat does not touch the bar.