I have been very inspired by Murray Carter's neck knives ever since right around when I first started making knives. Whenever I make a knife in his style, I give him credit, but they've never been "exactly" the same as his, mainly cause of my skill level as well as the different materials and methods I used to make mine. (Although 'he' actually sells a book with templates of his designs in it so that others can try to make them if they want)
Once most guys become interested in making a knife (or knifemaking rather), they will most likely find a specific design from a specific maker that they would like to replicate (such as you have with that Walter Brend knife), and they will try, but it obviously won't turn out exactly like it (probably even far from it) because it takes years to develop the skill to make something like that. Even so, always give credit to a maker (and even ask their permission) if you are attempting to replicate "their" knife. But by the time you have actually acquired the skill to make many of the knives you have loved, you will have most likely come up with you own subtleties in your own knives that make them "yours". The thing is, one millimeter can literally change the entire look and feel of a blade, and you will notice this as you sketch out designs.
I think you should just start making one man. Draw up your design, post it here and see what others have to say.. I can pretty much guarantee it will not look exactly the same as Walter's blade, no offense, let alone turn out like his once you have completed it. Just start making and try to stop worring about this and you'll get into a flow.
Here is an example of one of my Murray Carter neck knife inspired knives.. You can tell it's not exactly the same, but it's close enough to be noticed as his style so I give credit to him for it, plus
I know that it was my
intention to make a knife that looked like one of his neck knives (since I really like the style), so either way my conscience would not allow me to say that "I came up with it."
ETA: I should've just said I agree with what Stacy and Stephen and others have already said. (sorry, sometimes I don't read every reply before I type up my own

)
~Paul
My YT Channel
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