Victory Pete wrote:
"It is like keeping a truss rod very tight with a straight neck, it makes the neck more stiff and improves volume, sustain and tone."
Are you sure?
Tightening the truss rod puts the neck itself in compression. Loading a column in compression
lowers it's resonant frequency, which goes to zero at the stress that causes the column to buckle. This relationship has been used as a reliable method of non-destructive testing in aircraft truss structures.
I suspect that, in most cases, the load of a tightened truss rod is nowhere near the buckling stress of the neck, but without data it's hard to say. Some of those electric guitar necks are pretty long and skinny.
Also germane is the question of how you know this. How are you measuring volume, sustain and tone? Two of those, volume (or power, at least), and sustain are amenable to some sort of objective measurement, which should settle the whole question relatively easily. Have those measurements been made? We all hear what we expect to hear.