Just tested what in subject on a vm (so it has been a nested env) configured with 2 disks: 1x60Gb for OS and 1x100Gb for gluster.
Used node ng from ovirt-node-ng-installer-4.3.0-2019011608.el7.iso and almost all the problems had with RC1 here:
https://www.mail-archive.com/users@ovirt.org/msg52870.html
have gone solved.
The hosted engine deploy completed successfully and I'm able to access engine web admin and see the VM and its storage domain and connect to console.

The only persisting problem is that I choose JBOD in my disk config (because I have only one disk) and the deploy gives error about missing diskcount parameter in ansible playbook, so I have to edit the gdeploy conf file from the gui and add the section

[diskcount]
1

after that all goes well.
Good job guys!

BTW: is it correct hat for data and vmstore I only have the volumes configured, while I have to manullay create storage domains?

If I want to extend this initial configuration to 3 nodes, what would be the installation path to execute?

Thanks,
Gianluca