Gamo G Magnums

20mm OD. POA was the bull. 

More pronounced arc would be about it.
Having a 177 after 22 I prefure the 22 for hunting. Mildot scope made all the difference.
I find the 177 taking a lot of getting use too. Don't find that the trajectory any easier to shoot with than a 22, once you have your hold over sorted.
177 moves way more in wind and I'm finding that's actually a bit of an issue as its more sensitive to small channels of wind blowing between gaps. Has lot more effect on pellet.
Also not that keen on impact, 177 seem to punch through more often which is not desirable, creates less shock. However accurate shot placement and I think the penitration ability of 177 out preforms 22. That's due to them not expanding much.
I'd say a good scope and actually dialing the windage and holdover would be advantageous over holding it over through scope. I use holdover and trying to hold the exact place somewhere else on the scope I think takes more time.
I've also found that an accurate 22 with moderate power works fine. I'd be looking at something that still has enough power at 60m (which is about the range that hares let me get to, in open paddock after shooting them for a while) but able to take a head shot out to 80m.
At those distances accuracy far out ways to much power.
Which is why its a shame my gamo didn't preform at those ranges, it was by far the easiest gun to tote around for hours on end on farm.

I too was suprised when you said was a 45 yard hunter, as that is around the max range I would should squirrels with my sub 12ft/lb .177.  I know some folks using range finders and better optics than me would take squirrels and rabbits out to about 60yards with sub 12 air rifles.