1 week and it's still not finished?

...

That seems kinda long...

I have it set to 40 slots for downloads and usually it takes far less that a week for a 700M file...

I have set it to 10 upload slots and it seems to work fine (my upload bandwidth sucks big time).
You probably will never come close to that kind of speed however as you will either have to connect to a lot of T3s or even more DSL users. That's because, as you probably know, most DSL are assymetric (hence the A in front of ADSL), which means upload and download bandwidth are not the same. I have what is apparently called "lo ADSL" (or something like that) which basically means that my upload bandwidth is nothing compared to my download one. And that's not good for the network.
As for large downloads, I think that it could be because larger files are more complicated that they slow down the transfer. I can't tell you fer sure as I'm not a programer (or anything remotely connected to that).
Anyhoo, try increasing a little your upload slots (not per person) and also increasing the number of simultaneous dlds.

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iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

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