OK that definitly seem to me a Suport-Case:
If I remeber right just the installation was in average ca 15-20 min per downloaded Part here. Hacve you checked to have twice of the Library as empty SSD-Space since if you download all to the same SSD, where you want to install it you mioght need twice of the Diskspace to get the downloaded Files installed.If you run short with SSD-Space, perhaps you might think tto download to another HDD and install from there on your SSD. At least you can decide both times the path as well for the download as for the installation. May this might help.
If not try to contact: support@vsl.co.at