There's a way to configure an advanced ZFS pool on install?
We would like to install it on 12x disks with 2x raidz2 with 6x each. Basically a raid60 alike pool.
Not really. If you plan to store VMs on that large pool, please take a look at the documentation [0] regarding the pool layout and some maybe unexpected effects. For VM workloads, a RAID 10 like pool made up of mirror vdevs is usually the much better option.