I like to program my HT with these 5 pairs for working AO-27.  I start
with the first pair, using a non-standard split, and tune to the next
one as the pass progresses.

436.805 - 145.845
436.800 - 145.850
436.795 - 145.850  middle of pass
436.790 - 145.850
436.785 - 145.855

The doppler shift on the 70 cm downlink can be a little more than 10
kHz.  The 2 meter doppler is close to 3 kHz.  

I seldom need to use the 5th pair, except on high passes, and only when
the TEPR keeps the bird on so far south like it is operating presently!

Good luck!