Change Login URL – Multisite Domain Mapping Network

having a hard time finding solution for this

WP 3.6 Subdomain Domain Mapping network

need to change login URL to sidestep escalating brute force attempts

Better WP Security not working well at all – rerouted logins to 404 and didn’t change primary domain login/wp-admin URL… and database backup failed too

other plugins seemed to have a lot of unresolved issues in support forum so hoping to get a referral recommendation

simple htacess edits don’t seem to address the multisite / domain mapping issue

any suggestions on how to change wp-admin / wp-login URLs for multisite?

thanks