Custom install with PHP 7.2.9?

I am trying to setup Flywheel with XDebug, and to do that I believe I need to do a custom install (please correct me if that is wrong).

Preferred install is PHP 7.2.9 and MySQL 5.7 . When I choose custom install, the highest PHP version I am offered is 7.2, and MySQL 5.6. Is there a way to make the custom install match the preferred versions?

I’m in the same boat, need to xdebug with 7.2.9 in custom. Can we have an estimate as to when this would be available?