Please remember that I am a user with some technical background, not an administrator. Also, my responses are based on using Pervasive Workgroup and Maximizer, not Maximizer Enterprise. Finally, I've running Max 7 and have upgraded Max 5 to Max 6 and Max 6 to Max 7, but never beyond that.
Having said that, I have installed Max several times myself, so here goes :
1) Make a full backup of your data first, and test the backup by creating a new Max company that accesses the backup; This is Systems 101, BUT DON'T SKIP THIS STEP
2) Make a second backup and test it THOROUGHLY the same way - use this backup to practise the upgrade, and at each step make detailed notes that you can use not just to perform the real upgrade, but also for later troubleshooting in the event of a problem; DON'T SKIP THIS STEP EITHER
3) Personally, I would uninstall Max 8 completely first; The standard software uninstall won't do this, check the Support Knowledgebase for a document that gives full instructions - I know there's one there for Max 7 that should apply at least partially to Max 8 as well
4) For 10 users you should have a dedicated server, and a fixed gateway on that server
5) You should not need to be on the phone with Tech Support through each step of the upgrade - and I don't think it would happen anyway; The key is Step 2 - by the time you're practised the upgrade 2 or 3 times and taken detailed notes you should be ok
Good luck!
- R.