8 channel Analog Output 4-20mA Loop Generator/ 1-5VDC and 0-100%

I want to make a 3 digit 7 segment display voltage generator with a voltage indicator. but I want the display to be from 1-5VDC being 1VDC be 0% and 5VDC be 100% with a foot print as small as possible. so I want this to be workable with a fixed 250 ohm resistor and 1k potentiometer I want to have an 8 channel analog output. if you could also document how did you come up with the logic gates necessary to make that happen. No Arduino please. the one I hold is a single loop 4-20ma and it has STC15W404AS-35I-DIP16G LM358 7 segment 3 digit display. If is in percentage can get an LED working. I would like it to be presented in SMD form. there are a bunch of guides out there but I have no clue as to what I am doing so I would like to learn more from whoever does this project. the 4 channel picture attached is something I would like to do but with 8 channels in instead. also instead of having buttons to increase or decrease the analog signal out I would like to have potentiometers. also I would like to all of the loops be independent so I don.t have to control only one at a time. I would like a more simple design as shown in the single loop calibrator but with 8 channels. if you have any more question as to what I need let me know.