That looks beautiful!Maple DOES accept stains very well, will come out blotchy or not depending on skill of the person doing the work, requires sanding, and like anything else, may have problems. This is a stained maple neck and body, note that you can make it as dark as you want
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Roasting maple or other wood means that its heated in an oven for a fairly long period of time at moderate temperature - 250F is often quoted. The wood has no sealer or other finishes applied and the color will darken. Most of the time "roasting" is done for appearance. People do roast wood in their kitchen oven with varying degrees of sucess.
Torrification is the heating of the wood in a low oxygen atmosphere and is intended to cause the resins and moisture in the cells to change in a process similar to long periods of aging. Torrification is most commonly being done to spruce to force it to be like it was the top of a very old guitar. It will darken the wood but that is not the primary reason. You will not torrify wood in a kitchen oven.
There is a finishing technique where people wave an open flame at their wood to selectively burn some of the surface. Its not an effect that I care for.
Please feel free to do anything you want to your neck. Many aftermarket necks have some sort of sealer applied at the factory, that might create some interesting issues. Glues will soften at 150 to 250F, plastics (binding, marker dots, decals...) will probably melt. I use a little heat when I'm removing frets, it helps loosen them so they pull easily. Practicing on scrap insure that you will know how much heat and flame to apply, assuming you have some scrap. Then when the color is to your liking all you need to do is finish it.