Updating to the latest version of Invision has caused a few issues. I've reverted back to an old version of the theme so that Topics can still be accessed. Hopefully we will have everything back and working ASAP.
Like most RPG it depends on the group... If you have people that tend to be unreliable go for 5-6 in the hope that you will have at least 3 for any session... And be aware that things will get mad if they all turn up on the same week.