LT1001 have offset current 0.4nA typ, 3.8nA max (+25°C) with input bias current +/-0.7nA typ, +/-4nA max (+25°C). En is about 11-18nV/SQRT, specced 300nVpkpk, GBW 0.8MHz.
LTC2057 have offset current 0.06nA typ (+25C), 0.46nA max (-40 to +85°C) with input bias current +/-0.3nA max (+25C), +/-3.5nA max (-40 to +85°C). En is about 11nV/SQRT, no 1/f noise, specced 200nVpkpk, GBW 1.5MHz
Also 2057 have total supply voltage at 36V, which means those resistors at opamp power supply pins can be removed. I left them in place for now (not sure if ASIC current balance circuit would like higher amplitude, but likely be allright, as it's charge balance ADC topology, not voltage.), but even then voltage at opamp pins is higher now, about -16.5 and +17.3VDC, due lower opamp supply current.
Voltage is creeping
up, likely due to heat (blue line on graph, TEMP? data). You can see control meter - K2001 - also went up about 1ppm due warmer temp (3458A sits on top of k2001).
PPM scale for 3458A reading (red line) is green scale, went up 0.6ppm from power on state , sorry for misleading coloring
Purple line is +5VREF (wire from -12VREF came out, did not bother to reassemble everything again).
As a side note, I'm impressed with 3245A+LTZ performance so far, seem to be really stable thing, likely beyond my current measuring capabilities.