Bravo, Quinapalus! It is often the case that what appears to be a stunning composition is not as hard to construct as it seems, since the composer works in the opposite direction to the solver. However, in this case I find the construction very impressive, particularly since the skipped letters were pre-specified by the message (although arranging those clues in alphabetical order will have helped considerably). I agree with Texasetes that one cannot judge how difficult it would be without trying it oneself--but I wouldn't like to try.
I agree with others that some of the cues were a little iffy. For example, in "Kick ..." the correct word primarily refers to the thing contained, not the container that the answer is involved in making. And in "Mainz ..." the answer is unlikely to be heard where the correct version suggests. The latter involves a common error. For example, if the dictionary says that a word is Scottish, it may nevertheless not be correct to suggest that it will be heard in, say, Inverness, since many Scottish words are local to specific areas of the country.
The construction proves the specific case of ELM but not, I think, the general case.