Inasmuch as you have never shot a double rifle its apparant that you will have to deal with the recoil...those guns recoil in the order you mention, the .470 kicks hard, and the other two are worse..thats the real world...

The recoil of the double rifles is only a maidens caress in the fantasy world of the internet, where hardy souls can shoot the 577 and 600 N.E. with aplomb...

I would suggest you have Butch Searcy make you a 450-400-3", its much nicer to shoot, recoil is still there but far less than the others, and its a very capable round. Also I recently shot a 500/416 as I felt it was the caliber, but loaded properly it recoils about like my .470 it seems.