If it were my brew, I'd ditch the carapils and wheat malt, mainly to dry the beer out which will accentuate the hops incredibly well... I'd want it to finish around 1.10.1.012 tops. I'd replace their percentages with sugar, cane or corn.
I'd then do the magnum and 60 and 30 min instead of what I would consider a double 60 minute addition. Then I'd move all the rest of the boil hops which are all Cascades - great choice, to a 30 minute hop stand. Kill flame-> stir up wort to get it moving for 30 seconds or so without aerating-> toss in the 4 oz of pellets, cover the kettle and let steep for 30 minutes prior to chilling.
Prepare to taste and smell grapefruit.