Ravi, we have several bio feedback skin resistance machines here where I work. None of these uses a bridge type input. I think a bridge circuit is far too narrow in range for practical use. You would need several bridges, selected via a switch.
Skin resistance varies over a rather wide range between different persons and the equipment has to be balanced for whatever base resistance the subject has. Our machines have 3 switch ranges and a fine control pot to zero the meter needle at mid scale.
This is where your row of LED's will let you down unless you arrange them to read up AND down from a centre position, iow, two 3914's at least. A single one would need much too large steps to be useful and keep in range once the supject starts sweating, :wink: the smaller the steps the better the feedback. There is also a 'sensitivity' control on our units which does fine tune the meter's reaction to the input changes.
Regarding the electrodes, if you *must* use electrodes, the only types I found remotely useful are the rubberised black plastic ones as used with Tens machines. Any electrode designed for EMG, etc, does not work for this purpose in my experience.
For finger bio feedback, a Velcro strap collar with ss steel wool as contact material is easiest to use and works reliably.
Good luck
Klaus