@ fungus.. I was trying to remember what I'd read in Nick's tutorial and thought it better to err 'slightly' (10 - 20 mA..) on the high side as it is a slightly less severe sin than underestimating it.
Much better finally, less than more.
There are also the 'vampire currents' like the 1.6? mA Iq of the LM 358 and the various voltage dividers and the 3 mA for the power led as well as the (guess) Iq of the regulator that I'd place at 4 to 6 min.
My 'assumption' is based on prior experience with other PNP type pass regulators, I have no direct experience of the '1117 family but most of that type just add the control current as the load current increases.
Bob