I have that same Loos guage - given your crew weight, I think your diamonds are a bit tight for the conditions you describe. First, measure your pre-bend as other have recommended. Then loosen your diamonds to about 35 on your guage and remeasure.

Every mast and sail combo is a little different - on my brand of F18, I run about 34-35 on the diamonds in light to moderate breeze and increase to around 39 only when the wind is over 20-knots.

Let us know how your changes work out.