Shouldn't be as problematic as you think. The UI installs on the server. You then install an agent on each of your workstations. You can download updates but you get to choose when you deploy them out. When you deploy an update, any offline agents that come online should update automatically. Because of the agents installed on your workstations you can see which ones have and have not updated. For the ones that have not automatically updated for whatever reason you can redeploy the update to those specific workstations. I can't promise you will be problem free but I doubt it will be as bad as it has been made out.
The 70 laptops are taken home nightly by staff and therefore this apparently will make SOLUS3 deployment and updates very problematic; the laptops will be 'offline' when the updates are deployed. They may never get the update. They may require the update to be re-deployed. There is certainly no way of guaranteeing that when the laptops next try to run SIMS it will have been upgraded.