Acceleration altitude is 3rd segment. Minimum alt for third segment is 400ft. So this is the lowest.
There will be a divergence point between regular and EOSID. It's at this point that the two SIDs follow different paths. Once past the divergence point, follow the regular SID. (disclaimer: this is how we do it where I work and we are EASA compliant though not in an EASA country).