I been using servo.write() which I was under the impression took, as an argument, an int representing a whole number degree.
I changed my X servo to use servo.writeMicroseconds(). After doing a few relational math tweaks, on the Raspberry Pi side, I got the X Gyro bouncing around 0 degrees, with the X servo being tweaked by servo.writeMicroseconds(). I am really liking this change.
I'll watch, for a day or two, the results, perhaps a refinement here and there, before applying the change to the Y servo.
I've yet to determine the +/- mean X Gyro bounce around zero; that will take a bit of time.
Thanks for the heads up on servo.writeMicroseconds().