...do you have a single barrel nut and switch out only the barrel re-headspacing every time?

The reason I ask is I got to thinking (sometimes a dangerous thing), other switch-barrel rifles use a shoulder on the barrel cut to set the headspace and torque the barrel to the same spec every time keeping the headspace constant. Is there a reason that the same couldn't be done with a Savage by using the nut as the shoulder and pinning or silver soldering it to the barrel to permanently set headspace?

I'm looking to build a pair of switch-barrel Savages. I have the basis for one in a left handed .243 on an older long action. I will be buying a model 10 package gun (with Accu-Trigger at Wally World for a really good price) in .308 as the basis for the other. These two rifles will provide both of my sporter barrels. I will then build up the model 10 into a bench gun with longer, heavier match type barrels in probably .308 and .243 AI. I'd like them to be true switch barrels and not a headspace every time deal if at all possible.