Most large ring Mauser 98's are 1.1"-12 typically in a 1.400" receiver ring. This would give you a n average of .150 solid wall thickness, not including the depth of the threads. Small ring Mausers are .980"-12 in a smaller 1.300" receiver. They should have about a .160 wall plus the threads. We won't go into the large thread/small receiver or small thread/large ring variants here as they're a relative minority compared to the standard large and small ring configurations.
That said, .980"-12 should be fine for moderate sized cartridges like 250 Savage, 6.5x55mm Swede, 7x57mm Mauser and 35 Rem. This is per the "Mauser M98 & M96 How to build your favorite custom rifle" book by R.A. Walsh.
For the heavier loads you're talking about, you'll have to defer to someone more knowledgable than I.