For testing I made prototype using somewhat lower spec TS272C opamps. Is has some limitations but works quite promising. There is additional 5V and 2.5 V converters on prototype board that is not on schematic. As I trust in my DM3058E I hand picked and fine tuned exact resistor values. Initial conversion accuracy is really good. Somewhat problem is that circuit does not work well if separate mains referenced devices are connected to input and output like function generator and multimeter. Although outputs and inputs of these are supposed to be floating in reality they are not. Only thing floating (except for batteries) in my lab is power supply... as it is linear one with true isolating transformer inside. Measuring batteries, however works quite well. Besides 1:1000 range there is 1:200 range settable by jumper but it seems to be slightly off.