Hi Sandro
LM338 is of course a positive device, my suggestions at post above to replace the fixed 1 ohm /2 resistors is fine for the positive rail
with LM338 doing precise current regulation, The negative rail though needs some additional thought. It is possible to also use a 338
in a negative rail for voltage regulation, I will need to test to see if it can be configured for current regulation, but suggests instead a 337
with a pass transistor or mosfet on each to get the target 5 amps of current.