If you don't care about reception of real channel 4, the Winegard HD7694P has higher gain than the HBU-33 which would give you more signal to work with. The building penetration loss is an unknown at this point so the added gain of the 7694 is attractive.
The only con I can think of is that the Winegard can difficult to fold back down. If you get in in the attic and discover that reception is poor, it may be tough to get the Winegard back out without risk of damage.
I don't see any indication that WLS has ceased operation on real channel 7... yet. There operation on real channel 44 seams to be the goal, but they're currently operating the CH-44 transmitter under a Special Temporary Authority per the FCC.
http://transition.fcc.gov/fcc-bin/tvq?facid=73226
No need to block channel 7 at the antenna, that would require a filter and offer no benefit other than a lighter wallet. If you mean exclude channel 7 from your tuner set-up, that's up to you.
