I agree it'd be helpful to know the OG to recommend a bittering level... I know this is a really rough rule, and certainly would have lots of exceptions, but about the same number of IBU's as your gravity is a good point to start with for a good hoppy beer; I tend to go no lower than 10 IBU's less than your OG. IE, if your OG is 1.060, 50-60 IBU's is a good target.
My recent RyePA had an OG of 1.063, and my IBU's were 60. This was achieved with 7 oz hops, however, I did have some lower alpha's in there (East Kent Golding and Fuggle), and the hops were mostly clustered at the end of the boil to emphasize the aroma, plus 2 oz of the hops were dry (again, to emphasize aroma vs bitterness).
That being said, I think you'll be fine with the 4 oz...I'd think if you used the warrior for bittering (place at whatever time point gives you the desired IBU's), then use the others towards the last 15 min for aroma/flavor, dry hop with the ounce of cascade, and you'll have a great RyePA.