I like what some people have been doing here lately..pick your own 10 out of 50 listed or whatever..
That way if there are a lot of domains of 'questionable' quality..(domain valuation is very subjective anyway), people are essentially bidding against themselves until they reach the limit in their mind that they think is reasonable.
In a normal auction, they might second guess themselves if there is little interest or slow bidding.
And you won't have to give up all your domains..but maybe your best ones if someone who has a good eye comes along.
Would be helpful to see your portfolio anyway. Based on the domains I see on average around here, I would guess most people's portfolios wouldn't fetch very much, including mine. But just a guess.
People usually aren't out to spend a lot of money here. Most might not have room in their budget to go big on one auction. Unless the quality of your domains is undeniable. Even if they are good though, you will probably be giving a big discount no matter what, as others said.