Thanks for the very interesting thread RM.
Here's my $0.02, for what it's worth:
$664,000 x 2 = $1,328,000
10% of $1,328,000 = $132,800
20% of $1,328,000 = $265,600
$132,800 - $265,600 per year = very nice living (for doing what you like).
10%-20% per year shouldn't be that...