Galileo Open Service Navigation Message Authentication (OSNMA) has been transmitted stably over the last years and is expected to be declared operationally in the next months. While the protocol is very flexible, most of the parameters, such as key and tag sizes and cryptographic functions, have been already fixed in view of the operational declaration. However, some degree of flexibility remains in the tag and cross-authentication sequence. The cross-authentication sequence defines the satellites “cross-authenticated” by an authenticating Galileo satellite and is one of the main properties of the OSNMA protocol. It allows authenticating nearby Galileo satellites for higher redundancy against losses, authenticating data from satellites not connected to ground and therefore not transmitting OSNMA, and authenticating GPS or other data in the future. It has a significant impact on OSNMA performance: if the sequence is too long, many cross-authenticated satellites will not be seen by the users, limiting the optimal use of the OSNMA bandwidth, and with major impact in TBA (Time Between Authentications) and Time To First Authenticated Fix (TTFAF). If the sequence is too short, several non-connected but visible satellites may remain unauthenticated, also degrading performance. This paper presents an analysis with real SIS data from different cross-authentication sequences transmitted by Galileo over the last months, involving different tag distribution and number of cross-authenticated satellites including open-sky static, dynamic and urban environments. The work will show the degradation with suboptimal cross-authentication sequences and identifies current bottlenecks, proposing some recommendations for future sequences.