I have been reading alot lately about this style, it seems like the style first cropped up in the early 1800's in Burton-on-Trent as a strong lighter colored burton ale. The recipe I am looking at basing my future BW's on is the Barclay Perkins 1839 recipe as written about on the 'shut up about barclay perkins' blog. It's 100% base malt (mild malt specifically) parti-gyled and boiled for 4 hours to get the color right. The hops look like you are going for more of an american BW so I am sure it will be fine. Although I know alot of folks like the American BWs to be much lighter in body than the English types, and higher hopping rates as well (although reading that blog it looks like the historical strong burtons could be pretty highly hopped indeed). I did an all base malt BW back in january and with a 90 minute mash at 148 and the addition of 3 lbs of maple syrup I went from 1.096 to 1.016 and it's still pretty chewy. You might want to think about either adding some simple sugar to dry it out or mashing even lower, or both.
just my $.02