Hemi43, I certainly respect where you are coming from and your experience. Since you asked, I'm an engineer.
Fasteners such as wheel studs or bolts are meant to work in tension to apply a clamping 'normal' force, perpendicular to the hub surface . This normal force in turn creates a high frictional force between the clamped surfaces the surface of the wheel and the hub, or for the sake of this discussion, the wheel, spacer and hub. This frictional force is what transfers rotational torque between the hub and the wheel, as well as vertical forces from the mass of the vehicle, or any other loads in the same plane as the hub surface.
Now I would agree that in general, a larger negative offset will put increased tension on the studs or bolts. Perhaps more than the yield limit. However, this is not a function of the spacer, it is a function of total effective wheel offset. One can achieve the same effective offset by using a high offset wheel, or a low offset wheel plus a spacer, or a low offset wheel plus an adapter. The stud or bolt in tension will not know the difference.
Obviously there are other factors such as the cyclical loading and unloading of the studs as the wheel spins. As well as the lateral loading which adds further tension to studs. As well as the design of the spacer or adapter and the materials used for the studs, bolts, spacer, adapter, etc.
While a zero offset would be ideal, it is not achievable on our trucks if the wheels and tires are too wide, or the wheels are too small a diameter.
Now back to the actual scenario here, I am not advocating the use of 1.5" thick spacers, or so-called adapters. Neither are a good functional choice. Lets face it, anyone using them, including me, is doing so for aesthetic reasons.
If you want a truck that drives well use a 7" wide wheel with a neutral offset. Use 10" section-width tires and no extra spacers or adapters. I guarantee that your truck will handle and steer much better.
Cheers. And good luck with whatever you decide.