Been a while since I checked the specs but when I bought my Leupold 2x EER it had the longest eye relief and a great guarantee. This is mounted on a 480 SRH. Had no problems with it in a number of years of use.
I'm waiting on a Ultradot that I am mounting on a 480/475 BFR. This will be my first red dot. I have been told that they are tough as nails. I envision shots out to 100-125 yds max and more comfortably in the 75 yd area in the woods.
If I were buying for a X-frame 460, I'd go with the variable Leupold (2-6x I believe) as you want to take longer shots. Use locktite (red?.. the non-permanent type) on the mount screws or it will work loose quickly.
As your first scope on a handgun, you will be in for some learning and adjusting as I expect you are comfortable with scopes on rifles. Hint: Even from a rest, think in terms of quick shots versus "scoping" the target as you might with a rifle. Even from a rest, you will see an amazing amount of movement. I suggest using a monopod hunting.