I personally don't like high alpha hops on small 5 gallon batches on anything but an over the top IPA. I find it really hard to get the bittering right as the margin of error measuring out 20%AA magnum whole leaf is way too big. Even with a "cocaine" scale as Jamil advocates, whole flower hops are not a consistent homogenous product. And if you are doing a "classic style", you should spend the extra couple of dollars and use the right hop varieties....especially on styles that aren't hop forward. Late hops can cover up a neutral bittering hop but if your only addition is 60minutes, you will be able to taste the difference between high alpha hops and the same beer bittered with a low alpha aroma hop.