To be honest, I'd have not considered the 'single stack' magazine option. Really hadn't thought about the magazine at all, other than the need to lengthen it depending on the donor rifle.
Would appreciate any input from those with more experience in this matter. Even those with 338 Lapua rifles other than Winchesters. (Which is probably the vast majority of rifles chambered in this cartridge.)
I look forward to hearing about your Weatherby in both .338 cartridges, especially the Lapua version. What length barrel are you planning on using, and are you going to use a muzzle brake