This is such a subjective market and risky. You could hold a name for years without any offers and never sell it or you pick one up and sell it for a huge profit weeks later. So if you don't have patience or the money to wait it out this market is not the right one. Resellers barely touch them...
well, if the industry average percent to sell a name is 2% per year. and you have 20 names - statistically it would take about 2 and half years to sell a name.
That's only assuming you have really good names - crap names will never sell