Circuit can work with IRFP240/IRFP9240 (R30-10k, without C10,C11-100pF). Zobel network with 10R, 22nF and 4R7,10uH is on PSU pcb. MJE340/MJE350 must have heatsink (10mA), amp can work with +/-90V DC rail voltage with more outputs (R20,R21,R22,R23-100k instead 47k, R24-12k/1W instead 6k8).
What is the minimum drop voltage for good regulation and manageable dissipation? Thanks for sharing.
I suggest to set output voltage to get 10-15V lower than input unregulated voltage. Larger difference give better voltage stability but with more dissipation.