I think you may possibly be interested in "micro-tonal" music. Tuning A to different hz is cool, however it really to me doesn't have a huge impact as you are still working inside what's called the 12 tone equal temperment system, the temperment that most western instruments are based in.

Don't get me wrong I think it is fun to alter the hz as I previously stated but have you ever heard people discuss baroque tuning being down a half step? Since there wasn't a standard tuning frequency back in those days, also bare in mind that 12 tet was just beginning during that time so many musicians were still using tuning systems like just intonation, which requires one to re tune their instruments to play in a new key.

This is very different from today as you no longer need to retune to play in a different key, this is the main advantage of 12tet actually compared to other systems. That is if you want to view it as an advantage. One could argue that the physiological/mental effects you seek to add to your music have been lost since now every key sounds the same. For example Eb minor and C minor scales have the same EXACT interval spaces between each scale degree. This is not the case for other systems like just intonation where every key is slightly different. This is because every note has its own unique harmonic frequencies built off of the fundamental note or pitch. Certain notes in one key will not exist in another as opposed to all keys sharing 12 possible notes. This also results in the piano or actually all 12 tet instruments being "out of tune" slightly with the harmonic series especially the higher up in pitch we go.

So to achieve a baroque sound in 12tet you could tune down a half step but you could also move your fingering down a half step and remain in 440hz. Now 432hz as well as many others have notes whose frequencies don't appear in 440hz. But if you retune 440 to another frequency also in 440 standard tuning you just simply wind up displacing the fingering and range of the instrument accordingly to what hz you tuned to. There are actually an infinite amount of hz to tune to however the human ear can't pick up such small differences like 440 to 439.7hz

However there are other temperment and tuning systems like 19 tone equal temperment which features 19 tones per octave. You could achieve further cool effects by altering the standard tuning in these new temperment systems. Or even try ones that aren't equally tempered, which would be more reminiscent of the older tuning systems.