Just edited my last post a bit to clarify a bit better. Sounds like a good plan. I doubt you'll actually need the spot, although it won't hurt to record it anyway.
Looking at the photo, see how the soundboard of the violin is facing more or less directly upwards towards the middle of the microphones, and the lid of the piano on short-stick sort of shadows the direct line from piano strings to the microphones? I'd suggest trying the same array, shifting it to the right, back a bit so that it is placed more or less between the two instruments, and lower. You'll get less breath and playing noises from the violinist by moving a bit further back, and adjusting the overall height of the microphone array will tweak the balance in timbre between the violin and piano. As the microphone array is brought lower, off-axis from the top of the violin and begin to "peer further under the piano lid to the strings", you'll get more warmth and less shrill brightness from the fiddle and more brightness and "closeness" from the piano closer to a normal height listening perspective. Personally I question the whole "up high" mic placement tradition in classical recording, which to my thinking is mostly appropriate as a way of balancing the front/back direct/reverberant balance and timbre of the sections a large ensemble, where the instruments in back are considerably farther away and somewhat blocked by the instruments close to the front and the mic position. Most of the time I think it's mostly tradition and a practical way of getting the mics out of the sight-lines of an audience. I usually prefer a lower listening perspective which sounds more like it does when standing there in person, as the instruments were designed to do.
A lot of that is just personal preference though, feel free to ignore it!
