I would not recommend a plain wood thumbhole stock on a heavy recoiling rifle. From a practical use point of view, the thumbhole stocks are made to "fit" the shooter. The use of a 458 Lott or 460 Wby is to keep your rear out of trouble and for these uses a thumbhole stock is out of its element. Not fast enough to get into action in my opinion.
But for a thumbhole on these heavy kickers I would recommend either a quality lamianted wood stock or composite.
As far a brake, the 458 Lott is not a very good canidate for a muzzle brake
. The reason is that muzzle brakes
work off muzzle pressure. The higher the pressure the better the brake works. With the 458 bore, they have a pretty high expansion ratio and as such muzzle pressure will not be that high.
A brake will reduce recoil to some degree but nothing like you can expect from a smaller caliber, lower expansion ratio round. Even the 375 cal works much better with a brake.
That said, the JP will reduce recoil the most I would agree but damn are they ugly. The Holland and Defensive Edge would be my choice.
Personally, I would look into some mercury recoil dampeners installed in the butt stock if recoil is an issue with the Lott. They will help as much as the brake. also, a high quality recoil pad is also an extremely valuable feature on a big bore. I like the 1.25" thick Kick Eez recoil pads. These will take more bite out of the Lott then any brake will. They can be sticky though and hang up on cloths so if you get one and want to use it for dangerous game hunting, get some silicone spray and treat the pad so it is not so sticky. Kick Eez makes a spray for their pads that works pretty well.
Just my experience. I have a Ruger #1 in the Lott and love it. Now I just have to find a use for the big girl!!!