I need to move the stove top vent hood up approx 8 inches [both of us
hit our heads on the vent hood, can't even duck under it to cook.] and
the existing exterior vent cover needs to be replaced, so...

Tips on moving a vent hood up?

more importantly, I need a wall mount exterior vent cover for the
stove top hood.

We're in Arizona in a sometimes cold *and* windy.area, 25+F, 40kts

Don't want dust coming back through the vent and don't see any block
inside the hood itself.

This is new construction, exterior walls standard 2x6 filled, exterior
surface is stucco.

Right now, I sealed off the vent, and shut power off to the fan,
because
1. don't seem to really need a vent over the cooking area
2. the exterior vent cover is possibly the cheapest plastic cosmetic
grill I've ever seen. Not even mounted well, touch, would fall off
the house type mounting.

Rest of the house is built substantially so this appears to be one of
those last minute cosmetic touches.

Thus, where to get best cover?