I think he was just asking what the chances of selling are. I assume he invested quite a chunk to get a few good 4Ls.
I have no experience with 4Ls, but I have seen a good bunch of 4Ls in the reported sales here on NP. Therefore I think they can do it.
I think the important part here is your room for patience. If you need to have a decent amount of money back in a short time, BB might not be ideal since you will have less options to liquidate the names. However if you can cope with 3-4 months of no income from these names, I would give it a try. If you have 10 names for example and 1 will sell in 3-4 months, you have a great sale and a decent amount of your investment back. You will also have breathing space to see if another name sells in the coming 3 months. If they dont sell and you start to need some investment money, you can remove (part of) your names. Take into account that it takes a month for the names to be removed.
Hope it helps.