Go easy with the ginger - I brewed a spiced winter ale last year with 1/4tsp ginger, 1/2 tsp cinnamon, 1/8 tsp nutmeg and 1/8 tsp of allspice. It was a 23ltr brew with Coopers Dark Ale kit as the base and also had orange zest, prunes and black treacle along with 1kg of dark dried malt extract.
I only used 1/4tsp of ginger, but it was definitely present in the final beer!