Yes, in fact E* is bringing back the roof top pterodactyls to receive HD Broadcasting soon... But, and let me stress BUT... Customers are responsible for having the off-air antenna installed themselves or by a retailer.
Anything over 85 on 119 TP 11 and 110 TP 22 is acceptable, anything higher is overkill and will be blocked out by the same amount of moisture as if you have 125 signal on all
remove the dish off the mast and make sure the mast is perfectly (Or close) as possible to being plumb vertical (Considered Level or Plumb) Stick the dish back on, make sure you didnt change any dial settings at previous attempts and adjust untill you get signal ;)
Yes as long as your HD TV isnt at the TV2 location ;)
relax, the installer will know exactly what to do, just give him a few mins to determine what he has to do