I did the two antenna thing where I lived years ago. I was not
allowed to put anything on the roof by the landlord rules, so I had 2
antennas in the attic. I never even tried to combine them because I
knew about ghosting. I just had a coax from each antenna come to a
switch *made for this purpose*, which was near the tv. The switch was
either one or the other antenna. I'd just flip the switch for the
best reception, and I got to know which setting was best for which
channels.

LM

If he can't get out of the attic your method will certainly work also.