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I make a lot of necks (for electric guitars) and I use different truss rods for the different types. Of course on a 1-piece neck I use a vintage-style 1-way rod, on 2-piece necks I sometimes use the same or I use a 2-way adjustable rod. The 2-way is always the easiest and most versatile, but I prefer the "old-school" 1-way rods not only for the fact that I like the skunk stripe and the plug at the headstock, but I think the tone is better; 2-way rods brighten the tone a little and I don't like or need that when I make a Maple neck and a body made from Northern Ash.
I've talked to many different Luther's on this and I get different input every time. I usually pre-bend the rod with a tapered shim that peaks in the middle of the channel at about 1/16-3/32" and then I sand about .005" relief when I radius the fingerboard, but sometimes I don't pre-bend. Is there an absolute best way to install a 1-way rod? I would use them all the time because it's what I prefer if I knew I could get it right every time... because trust me... sometimes it just doesn't work out and I get no adjustability so I hack the end off the neck and pull out the rod and start over (cursing:R all the way).

Pre-bending a 1-way rod is probably the best way IME. Otherwise one runs the risk of tightening the nut and not see much happening if the rod does not take a bend on its own. With a 1-way I also tighten the rod slightly before levelling the fretboard -to get a very slight convex FB that I will flatten-, so it can go both ways afterward. Just in case.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Try a bigger shim or a jig to rout a deeper curved channel.The thicker the neck the deeper the rod should be set. The deepest point should be under the 7th or 8th fret.Leave about .100" of wood on the back side of your truss rod.Make sure the holes are at the bottom of your truss rod trench so the rod will bed consistently along the entire length.About .010" relief at the 7th fret is a good place to be.
Hope this helps, good luck

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How long is that in luthyears?

If you have a stiff board and the rod is far enough toward the back, it doesn't actually need any curve or bend at all. Some of the old Gibson rods were actually placed in the neck with a reverse curve. They were far enough back that even though it seems they would want to push the neck in to more relief, they were so far below the center of the neck that they compressed the back and countered string tension. Of course a bit of curve will make the rod more active, but I'm convinced those old backward Gibson rods contributed toward stiffening the neck.

I've always been preferential to the conventional compression rod. I'm quite convinced that force applied from a self-contained double action (force perpendicular to the neck, usually focused at the ends) has a different effect from the compression rod (force parallel to the strings on the opposite side of the neck), both in stiffness and consistency of adjustment. Though it will certainly vary with how they're fit and how the neck is constructed, I find more double action rods being overactive in the first few frets than compression rods. There's also little doubt that the difference in mass and stiffness have some effect on tone.

I say install it as far back as you comfortably can. .100" from the back should be fine. I typically run the rod straight on the bottom from about the 5th fret to the heel, and a slight curve upward toward the nut - I'd guess around .080". Basically just fitting it in to a flat slot, allowing the welded end bracket to prop up the anchored end, thus creating a slight curve at the end. I also feel it important to anchor the headstock end as far toward the headstock as possible, under the nut or beyond being ideal. Then clamp a stiff fill strip above it, and it's always worked fine for me.

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Eschew obfuscation, espouse elucidation.