Thanks, gentlemen.
RonS : prefer to keep current to ~20mA peak for longevity respecting suggested operating point instead of pushing it.
Expressing the original question in another point of view; for the shown circuit, how many LED emitters will yield more luminosity ?
RonV: seen that chart before, for a single emitter. Seems from it, adding a number of emitters in series to the point of decreasing each current peak to about 64% from the recommended working current of a single one would be more luminosity efficient.