Norco,
Plus +3 will give you a zero of 280 to 310 yards, somewhere in there depending on your bullet and velocity.
Suggest sighting in at 250 yard 0.
This is appx. :
+2.3 at 100 yards
+1.9 at 200 yards
-3.2 at 300 yards
-14. at 300 yards
This is using 140gr bullet at 3100fps.
It is best just to 0 the gun at 250 yards (if you have a long enough range) then you know you are where you want to be.
Get it to appx. +2.3 at 100 then move out to 250 to really dial it in.

This means you can hold right on out to just past 300 yards with no worries of being too high at shorter ranges.
350 hold top of the back and 400 hold about 5" over the back.
A mule deer is appx. 18" from top of back to bottom of chest, smaller whitetails will be less, appx. 16".
Go to www.biggameinfo.com there is an easy to use ballistics calculator there that will give you all this type of info.
Just plug in your bullet info, velocity, and the zero range then the program will calculate your trajectory for you.