It's great to hear that you tried it and it worked for you, Azelor. I am pretty curious about your experiments/WIPs.

@madainsel: yes, the technique can be used prior to some Wilbur passes. I've tried that with a lot of success, but you need to be careful with the settings and thread carefully. That's because elevations at lower altitudes can disappear very quickly with Wilbur. Wilbur will work wonders at a scale of 100m per pixel or less, and to do a map with my technique at that scale is pure madness, so you really need to know what you are doing expanding the map step-by-step, "wilburing" gently in each stage.
The main point, though, is that Wilbur will accept a grayscale heighmap, with a linear proportion to the amount of white in each pixel. You need to work out that scale and colorize each level accordingly - then merge all layers (in a separate file, obviously) and save it as .jpg or .png.