First let me apologise for not responding I'm not getting email for this thread for some reason.
I use (my) market value x 20% with consumer price indexing every January. So a 25k domain would have a 5k annual lease price indexed every Jan.
However the rev on this deal was driven by a percentage of rev of the proposed marketing plan. They sell advertising across the US and expect to generate around 25-40k/mo in rev.