Here's an analogy which might be hard to follow, but I'm going to try to make it a worthy analogy:
Whether it's a mouthpiece or an instrument, parents of school children have come to me shopping for second instruments for their children and asking which make and model will be the best "forever instrument" for their child.
Make it clear to them that there's no such thing, and the reason there are so many different choices at the top price range is because there are so many different tastes and so many different beliefs. I then tell them that the best thing they can do at this point is to be resolute that the instrument that they are shopping for now - and end up buying is the last instrument that they will pay for for their child, and to raise their child to be able to be self-sufficient and pay for their own stuff from at least three or four years from now onward.
Okay this kind of sucks as an analogy, but the only way to learn about sticking stuff together - and increasing the chances that the stuff stuck together will end up being a fine instrument - is from experience and from having done it before. The more messing around with projects such as this, the more knowledge and instincts we gather, and the more that we sort of begin to "know" that something is likely to work or that it's not likely to work.
The child will grow into an adult and will encounter all of these choices in instruments and will eventually know better which ones might be best suited for them and which ones might not.
See? The analogy sucks because it's so tangential, but that's all I've got.
(These days, most everything that I stick together ends up playing pretty well - luckily, and I'm not particularly interested at all in the "journey", but only arriving at the destination. In other words, I find building instruments for myself to be tedious, and really am only interested in the instrument that results from the work.)