Basically, if the rifle is properly made, it will stay on the face. If not, it'll shoot loose and nothing you do will prevent it from happening (delay, yes...prevent, no).
With regard to a good lube, Vaseline is what the old, English gunmakers use. Rub some on the mating surfaces, and carry on.
I'm quite sure all double rifles will sooner or later come off face, but proper care will make it last a lot longer than most here will keep a new double rifle.
I have a 500-450 no1ex Westley Richards double rifle that was sold out of the London store in 1892, and it is still on face and as tight as a jug.
It is true that the old makers used Vaseline for lube in there doubles, and some may still call what they use Vaseline, but I can assure you it is not drugstore Vaseline.
There are modern greases Like the
MILITEC-1 synthetic metal conditioner that are far better than Vaseline!
1~ stays in place, and lubricates in severest conditions.
2~ Excellent water wash out resistance
3~
Superior shock-load protection<<<<<<<<
4~ Reduces corrosion, wear and Galling
No 3 is very important giving off face protection
Nothing will last forever but I see no harm in trying to give a very expensive double rifle some help to live longer!
I used to work for a company owner who soaked his bolt rifle in MacMillan Ring free Motor oil between hunting seasons, because that was what his father had always done.
I don't think anyone here would do that to a double rifle, but I may be wrong.
........................................Mac