The attached score shows that I have shown 2 tied crotchets in 2 different ways. The trumpets read a minim and the trombones, who have a quaver to play before going into the next bar have tied crotchets. My reasoning was that as the trombones were going to play another note in 'that' bar, it might make it easier to read. However I think I might have transgressed some rule in giving the trumpets a minim which crosses the imaginary mid-point of the bar. (The piece is in 4/4 by the way).
So could someone point out the 'correct' way please as I am clearly not certain.