Dating and origin based on Farrington (2012), 142 note 456. Heliodoros was victorious 4 times in the Spartan Ourania, refounded in 97-8 A.D., which gives a terminus post quem for the source, IG IV 591, of 109 A.D. Farrington assumes Trajan gave Heliodoros his Roman citizenship by 117 A.D. and estimates an average career length of 25 to get at a career start around 90 A.D. The source gives many victories. - PK
For these Olympic victories, cf. Farrington (2012), 143 note 457:
Three Olympic, five Pythian, five Isthmian, four Nemean, two Actian victories, among others. The Olympia referred to here are clearly those of the periodos, at Pisa, since they are grouped together at the head of the inscription with the Nemea, Pythia, Isthmia and Aktia(ll. 5 –6). Heliodoros cannot have won at Olympia as a kitharodos, as there was no event for this discipline at the Olympia, as he did at other contests, and his discipline at Olympia was pre-sumably that of the herald, as is suggested by the presence ofhis phonaskos(ll. 10 –11).