I had a fugue subject in mind and was looking for some guidence as to how to approach the structure of the exposition of fugues in modern compositions. I could simply answer at the perfect 5th as was done in common practice fugues (followed by a subject-entry at the octave then another 5th answer), but the answer at the 5th in tonal music had a real purpose to it, and to simply use the same technique in modern composition because nothing else can be found seems a bit like using an empty shell.
So I was wondering if any of you had experimented with alternatives, and if so, which seem to work best. I've thought about answering at the tritone, or possibly distributing the answers in such a way that they movethrough a tonal "cycle" by the start of the middle entry (such as successive entries at the minor third in 4-voice fugues or at the major third in 3-voice fugues). But the problem with "symmetrical" distributions such as these is that they seem to eliminate the retransitions that are so often found between the 5th answer and the octave subject-entry in tonal fugues, since each subject or answer will be followed by an entry that is the same distance below or above as the first entry (since the subject will be constructed to allow for an answer at the next level, say a m3, and the process can just be cycled with the next beginning another m3 above, and then another, etc.) and - since retransitions can carry aesthetic as well as simply tonal transitory function - these would be useful to have, but would also be difficult to justify if the tonal process is as cyclical as the above example.
So, long story short, what have you guys found about fugal exposition structures in your own experience?
EDIT: also, which modern composers would be good to look to for such questions? I know Barber has the wonderful fugue at the end of the piano sonata, and I'm sure Schoenberg - with his vast knowledge of tonal harmony and counterpoint - also has some great contrapuntal textures, but I don't know any fugues of his.