I don't like really bitter beers myself. My IPAs are first and foremost about aroma. Some are bittered just enough to balance them some others have more bite and dryness.
I like magnum as a bittering hop because it's a high AA hop so you don't need a lot and it's a clean bitterness. For a pale ale I'd shoot for something like 20-24 IBU from my bittering hops just for balance. IMHO FWH give you more flavor so I always use bittering hops with FWH.
The PA I'm drinking right now is a lot like a Firestone Walker Union Jack. I did centennial FWH for 16 IBU, then bittered with magnum to almost 25 IBU. Then I did 14 IBU at 5 mins and 3oz DH. It's 55 total IBU which is high for a PA per style but its really smooth and balanced with lots of juicy hop flavor and aroma.
I've been late hopbursting more lately instead of whirlpooling. I think whirlpooling gives great aroma early on but I don't think it's as stable as the late hopbursting which seems to create aroma that lasts longer in the keg. Just my opinion YMMV.