One of the troubles with adjustable truss rods is that they act like magnets for inexperienced "fiddlers" (as in "fiddling with things", not our esteemed violin-playing colleagues!).
Some of the most tiresome repairs I have had to do have resulted in overenthusiatic meddling with the "adjustable truss rod".
I'd be with Grit on this. A well-made guitar doesn't actually need an adjustable truss rod and I wouldn't personally use one. If I were back into guitar making though I wouldn't necessarily make my guitar with an absolutely "straightedge" neck as with a lowish action and correct neck set you would almost certainly get string buzzing mid-fretboard.
I can see I'm going to have to quickly finish coverting one of my basements into my new workshop and get back into this game again as soon as possible. All this mahogany and grain and rosewood and truss rod talk is getting too much for me and getting me fired up again! (P.S. First project is already earmarked as I already have the materials and ideas for it: an original design, "thinline", standup fretless bass). If anybody's interested in progress I'll post up pictures of progress on my website and provide blue clickies! You'll have to be patient though, I'm not the fastest of workers and that "day job" stuff tends to get in the way all too often!)
All the best