I was think that direction, combining the two attach examples
will do the trick, and still tinking about mis use a 78xx in to a const current driver.
Gone build up the breadboard.
That should work out, however your specific 'load' my require a grounded 'load resistor', which that second design doesn't appear to support? Also I would suggest you consider adding a little 'fudge factor' of a little more gain then needed and an adjustable offset control. Industrial E-to-I converters almost always included two trimmer pots to fine tune the 'zero' (offset) and 'span' (gain), to allow for fine calibrating the whole system.