So far, I have been mainly using the tympani in my orchestration of the Pathétique Sonata for the purpose of adding an accent. It might change later on to having a more important role but right now, it is just an accenting instrument. Because of this, I feel that I can give plenty of time for the tympanist to retune the drums if I have to to keep the accent consonant with the rest of the orchestra. I also think that most likely the tympanist would have tympani pedals to raise the note without retuning the instrument. So far, I have been keeping it forte because of its accenting purpose.
But I'm wondering whether it would simply overpower an orchestra that is at piano if the tympani stays at forte. I mean, the distance between the tympani and the woodwinds and strings and the sheer power of the brass makes me think: "No, of course not. It is too far from the more mellow instruments of the strings and the woodwinds to overpower them. Besides, the brass, even at a piano dynamic is very powerful, especially if you include the heavy brass (tuba and trombones) as I do in my orchestration."
But, am I right in that assessment? Or should I lower the dynamics of the tympani a bit to something like mezzo piano when the orchestra is at piano so that it still sounds accented, but not overpowering?