Ok, so just focusing on the input bias resistor, that must go on the (+) input to Vcc/2, this is here to create an even input impedance for both inputs, to reduce the error caused by input bias current. =>The impedance must be equal on both inputs.
Now in the
left hand side of post 17 The (+) input sees an impedance of the blank resistor, whilst the (-) input sees an impedance of R1||R2. =>The blank resistor must equal R1||R2 to minimize the error effects of the input bias current.
The problem with the right side of post 17 was that no current, or very little, would flow, causing problems. => Wont work
=> Given up!!!
With the coil I have, I want high input impedance amp as to not load the coil and dampen the resonance. By putting a 10M ohm bias resistor in the values of R1 and R2 have to be exceptionally large to offer equal resistance and would lead to noise and other bad things. Without the bias resistor the amp would be open to having an input bias current error, which would result in a DC offset (not sure), but it would result in a high input impedance without the need to have large, additional, resistors.
The new problem I have is which is more important, high input impedance or no input bias current errors.