Do you have the supercat 19 or Supercat 19X or 19XL? The standard 19 has the 28 ft 9 in mast which has spreaders that are not swept back. The Supercat 19X and XL have a mast that is 33 ft long with swept back spreaders. This mast is a prebend. I happen to have both rigs for my 19.
On the prebend (19X) Adjust to your preference. If you find it overpowered reduce tension to where the mast is almost straight or straight. (I found this to be the case on mine.) If you want more power tighten on the diamond wires. Mine came from the factory with about 8 full turns on the turnbuckles.
On the standard 19 mast I have mine snug where I can go up about a foot and touch the wires to the mast.
I hope this clears up a little of the mud. I usually sail with the smaller rig. The boat handles better in the rough stuff especially single handed...