Pete's suggestion is solid, but you could try to make two small batches with the hops - one with the American and one with the European. It sounds like you are going to use extract with grains, so you should be able to make it work. Try a Cali Common with the American hops? Usually made with Northern Brewer hops, but readily subbed with the Cascade and Chinook. Here is one recipe from BYO (extract with grains - For your use, I would use a half ounce of the Chinook for the 60 minute and 15 minute addition and the Cascade at 1 minute):
Uncommon Common
(5 gallons/19 L, extract with grains)
OG = 1.054 (13.3 °P)
FG = 1.016 (4.1 °P)
IBU = 41 SRM = 11 ABV = 5%
Ingredients
5.5 lb. (2.5 kg) light liquid malt extract
1 lb. (440 g) Munich liquid malt extract
14.1 oz. (400 g) Great Western crystal malt 40 °L (or similar)
7 oz. (200 g) Briess Victory malt 28 °L (or similar)
1.75 oz. (50 g) Crisp pale chocolate malt 200 °L (or similar)
5 AAU Northern Brewer hops (0.77 oz./22 g of 6.5% alpha acids) (60 min.)
8 AAU Northern Brewer hops (1.23 oz./35 g of 6.5% alpha acids) (15 min.)
8 AAU Northern Brewer hops (1.23 oz./35 g of 6.5% alpha acids) (1 min.)
White Labs WLP810 (San Francisco Lager) or Wyeast 2112 (California Lager) yeast