Didn't have time to finish text: much of this is a direct answer to some specific comments on OboeBBoard.
To be finished soon.

Don't be fooled by the apparent complexity of my sketches: it is very easy to scrape this way, just very hard to explain in written text and drawings. Note also that they are figurative: you won't see exactly this when backlighting (or translucence compared to an dark bellied placque), but you will get the impression of this. Even the very short-scraped French reeds will do this to some extent.
You can get the "impression" of 2 scketches at the same time: that's OK: it means you understand what's going on. Civil and mechanical engineering deal with tolerances and local minima/maxima. Computer and software engineering deal with methodology to solve given problems, preferably in a reusable and scalable fashion. This is why I don't do precise measurements but rather focus on the understanding of how things affect each other.

Not really any "no scrape zones", but more a matter of loosing support. Remember your courses on vector mechanics: if the tip to back vector becomes too long with too little strength IN COMPARISON to the outward-inward resistance, then the reed will go unstable.	[0] Layers in cane.
Tying is just as important as the scrape. NEVER tie beyond the end of the staple: really important is that the blades to not 'slip' or overlap side to side. One trick I use (this had been taught as a standard a looonnnng time ago) is to use a nail file (emery board) to flatten the edges of the cane. This way, instead of having peaks pushing each other out of the way, small flat surfaces are resting on each other.	[1] Helping the shaped cane not slip.
	[2] Most of the scraping before chopping.
	[3] At this point, it should play - hard, but all the range.
	[4] Not UFO! looking down reed, proper thickness (thin sides)
	[5] Smoothing the blend and make V at same time.
If your purchased French reeds are slipping, then everything I wrote might be for nothing. For me-myself-and-I, slipping is just plain trouble. I have tried shaving off the sides of the reeds when they slip. The benefit to this was debatable at best.	[6] Thinning the rails: be sure heart stays thinner esp. at the sides.
	[7] Frequent result of removing bumps from heart and/or tip
	[8] Fix after chopping to 'back-up' blend.
	[9] Can't close: reduce bark.
Opening - this gets tricky: both the spine and the "rails" affect both the opening and the strength, but in different ways. Usually, I start by getting rid of the spine. But if the inside of the W is too thin, then the reed gets unstable. This can often be remedied by shortening the heart and chopping short. If this still doesn't close the reed, then all the bark of the W goes. The tone usually gets warmer with this. Clear tones usually come from not enough difference in the heart between the middle and the sides. Ironically, it has happened that thinning the very tip for better response improved the warmth of the tone.... go figure!	[10] Thin towards front: never 'holes' or bumps.
	[11] This is often enough, esp. with long, thin cane.
	[12] If the reed is too hard or open.
	[13] Thin down spine before rails.
	[14] Some of my reeds are satisfactory looking like this.
	[15] Frequent final look: most important is the sense of proportion.
	[16] Most frequent look of my reeds.
Reeds that start of hard often end-up looking like this. At this point, the bark from the W can be completely removed, leaving a straight line between layers 1 and 3 of Fig. [0]	[17] No 'windows'.