I made one for my brother, who teaches classes in solving them; it was one of those which requires a little subject knowledge, so one clue unlocks several others.
Here are some of them:
Concert for 51, 24 (5)
Going both ways round the islands, so previously 24 (8)
Split 24 (4)
(8 across) One 24 of 3, 5 and one or other in soprano section (9)
Third 24 with 8 and 15 18 pigeons (you win one, you lose one) (8)
(15 ac plus 18 down) 24 almost put a dead bird in front of the merciless duck (7, 7)
Link about East German 24 (9)
and 24 itself: Part of note you can hear (5)
Some others I was rather proud of:
"Band of Gold": first entry in pop charts (9)
Sounds like Monica will commit identity theft (8)
Welcome refreshment for aficionado (7)
Good book about foreign trade, endlessly upholding wildlife provision (9)
Performing arts supremo (4)
Credit check (4)
Tucks around browser in monkey houses, so we're told (8)
I haven't included all the clues because my brother told me off for making anagrams of synonyms, he thought that was over-complicating it...
...even though he said he did like
"24 with soft kinky bottom (5)"
which includes an anagram of a synonym which would have been censored out.
So this means that I can't give you any helpful letters - however, if anyone solves any of these, I will include any letters from that solution with any clues it affects