Hello Rick.
The harmonics issue is certainly part of the story as related to stress relief or making up for it.
One nice thing about the big bores is that they are effectively bull barrels which solves part of the problem. Even though the hole is bigger, they are shorter compared to their diameter.

In most large caliber rifles (+40) most manufacturers just don't see longer range accuracy as great of a concern and closing the distance is the job of the guide. Fully bedded stocks and sling swivels on barrels just don't make that much of a difference

I have been bedding using the same treatment mentioned above, where the barrel is bedded just beyond the action (c 1"), mainly because I don't want pressure from shooting sticks/bipods or a sling to effect the point of impact. (although that changes when the sling is on the barrel which goes back to the big bore-short(er) range thing)

As also mentioned above, if you have to keep a stock from splitting, do what you have to. I am a big fan of magnum crossbolts as many stocks split in front of the trigger which will definitely throw off accuracy (and eventually destroy the stock).

You can also use steel/ aluminum blocks, pillars, etc as being non-compressible (less affected by atmospheric effects on the stock) so at least your screw tension stays where it should.

If you are interested, you can always cryo treat the barrel for better consistency.

In my limited experience with cryo treatment, it seems to cover a bunch of sins. I have only had two guns treated, but both worked so well that I didn't have to do anything extra to the to make them shoot.
One single shot rifle in 280 had groups that typically went: center,2", 8" for the first three shots from a cold barrel. No amount of bedding would help and the barrel was obviously not correctly stress relieved. Sent the barrel out for treatment and the same rifle consistently shoots into 3/4".

Good shooting.

Tom