controlling quiver colors with C arg

Question:
If I have an array C with values for the arrow vectors' magnitudes, how can
I control the magnitude levels & colors that are assigned to the quiver
arrows?

I successfully managed to plot multi-colored arrows using the 'C' arg, but
I'd also like to control the levels & colors, and also plot a colorbar for
the arrow magnitude values.
Is this possible?

Please help,
Thanks,
P.Romero