Voltage step up for bidirectional current source
If you are going to use a step-up, boost converter for the +30V, then it is very simple and economical to create the negative of that using switched-capacitor given the current requirement is low.

The schematics below shows the typical boost output stage in L1, M1, D, C1.
C2, D2, C3, D3 are the addition to generate the negative voltage. The negative voltage tracks the positive voltage minus one additional diode drop. If you don't want the diode drop difference, make D1 into 2 diodes in series (that would waste 0.7V in the +30V output).







simulate this circuit &ndash; Schematic created using CircuitLab