On paper, you want a pair of 20H 75mA, and half the capacitance.
But caps are cheap. If you stick with the 2-ch cap value in a 1-ch amp, you could stay with 10H (75mA) or maybe less.
As Johnny says, 10H and 150mA will often run like 15H when only passing 75mA. It isn't very critical, as long as you do NOT exceed the current rating, and the inductance is "close".