Client power should be adjusted to match the AP power settings.
Maintaining a higher setting on the client does not result in higher performance and it can cause interference in nearby cells.
Antennas give the WLAN three fundamental properties:
Number of users per AP 15-25 (data only)
limit data rates
Changes to the channel topology causes clients to reassociate, and calls to drop. Change sin AP power do not impact client connectivity.
Range is generally affected by a factor of a 30% increase (approximately) for every halving of a data rate.