Great info provided to you so.

Agree that a double is NOT a bench gun, nor it is of much value to "test" it out on a bench to "see where she shoots"... Must be held in the hands.

The first time I shot a big double I made sure I was wearing a quality shooting jacket with heavy padding. It made a world of difference. Actually I wore TWO.

Shooting the guns before you do anything is sage advice. Plus, shoot lower weight boolits and lower powder if possible. So much depends on the charge and weight of the boolit you are shooting out of those guns.

Plus, the first day of shooting can be deceptive. It is a wise idea to use the first day just to familiarize yourslef with the gun and definitely shoot standing or with a brace up front but definitely with your front hand holding the gun. Don't make any rash conclusions. Let a day or 2 go by and shoot the gun again. I have done this on a few occasions and 'discovered' my first impressions were NOT always right. I needed to marinade with the gun. Felt recoil for me is often LESS on subsequent days than it is the very first time I shoot a big gun.

If you find you need to reduce the felt recoil there are very good after market pads like the Pachmayr Decelerator, 1 inch thick.

Also, although balance is effected, try Edward's Recoil Reducers. I think they dramatically reduced felt recoil in my double.