Whoever's rifles you were handling clearly was misinformed about how much torque is generally required to have the cheekpiece set for the shooter to achieve the appropriate height. Your resting your cheek on the cheekpiece, not parking your pickup truck on it, the McMillian stocks employ an un-anodized/bare piece of aluminum for threading in which the thumbwheels mate up with the riser bar for the appropriate height. Not much torque is needed as again you are not (or should not) be pressing down with an absolute insane amount of force, while that is a downfall of the stock system (with that cheekpiece as its selected option) in my mind, a simple re-threading job to an upsized thread will suffice (with the appropriate corresponding thumbwheeler threads of course) and then taking note to NOT OVERTIGHTEN the screws as bare aluminum doesn't play well with threading constantly. The bare aluminum block is permanently epoxied into the rear of the stock, so it would require a pretty good amount of machining for removal/replacement to something stronger.
The folding stock systems employ a more robust setup, and one that does NOT have the threading pitfalls of the McMillian...