you could add another pound of base malt if you want.
i've been really lucky and get great efficiency out of my setup. 75% or better (my porter ended up a little higher even)
my lhbs also has some brand of 2-row that is real easy to work with...very modified, converts in like 40 mins, and he gives it a proper crush.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10