The attachment path was spot on but for Customavatar the value: ./customavatars which was/is correct didn't work. I had to change the path in there to home/useraccount/public_html/forums/customavatars in order for it to work.
The attachment path was above the webroot: home/useraccount/attach, in case that was the problem. Nothing I couldn't figure out, but could cause a problem for a new admin.
Currently running the import on a 170,000+ user database. Based on the time to complete the first 25% of the user table, it looks like it'll take a bit over 5 hours. Will update later...