is the LT6370 suitable for providing a signal to a right leg drive circuit by splitting its RG into 2 resistors and using the signal at the center tap for the RLD circuit?
LT6370 is suitable for the Right Leg Drive (RLD) circuit that you're asking about. LT1168 datasheet (Figure 8) shows a dual supply implementation. LT6370 can be similarly used.
The part I'm not sure about is that you're doing a single-supply implementation and the RLD electrode will be at 2.5V DC. I don't know if medical instrumentations allow a DC supply voltage to be applied to the body or not?