I'm going to give a very honest answer, but I do so in the interest of helping you make a good decision:
I have been a 3-4 times a day orgster and I have gone some time without visiting also. I think after a week you start to break the addiction, and in 2 weeks we might lose some people permanently. Longer than 2 weeks and you will need to come back with things really looking good. I understand the huge volumes of data you have to sort but if people come back to the site after 3 weeks only to find that the stuff they need is missing or impossible to find you might lose more people.
Bottom line is you have to look at what you will be offering and question whether or not that is enough to get people to reengage the site. Personally, in almost all cases I came back to the site after an absence to find a post on a mod or something like that. In looking for that I found posts by people I know and gradually found myself pulled back into the community. So you need to get good how-to posts back on the site before reopening it.
Another thing to think about is it's better to have the site down once than many times for smaller time periods IMHO, as long as you don't go away too long as I have already discussed.
just my 2 cents.