How much Saffron to use?
I agree with the others that 1 gram is way too much saffron.  Unless you're making one of those huge outdoor pans of paella which feeds 20 people.

Exact quantities depend on how much paella you're making, and the freshness of the saffron involved.  I tend to use a hefty pinch, which would be around 12-20 threads, for a paella for 6 (2-3 liters).  I'll adjust that downwards for very fresh saffron, and upwards for old stale saffron.  You can tell how fresh your saffron is by (a) smelling it, and (b) soaking it in a small amount of warm water.  Fresh saffron will smell strongly floral/spicy, and will turn the water bright yellow very quickly.

I like saffron a lot though, and also tend to err on the side of more rather than less.