Hello Sam (you are the most likely to read this post, merci)
When I am sharing one or more big files that are popular, it takes all the upload slots without giving places to small files that are fast to upload. Two suggestions:

1)make a big files queue and a small file queue à la Shareaza (one queues for files less than 10megs, one fore bigger files).

or

2)make it possible via the library (or the upload pref panel) to limit the number of simultaneous uploads of one file.

Seriously I prefer the second option, because the multiple queues in Shareaza are somewhat a "bordel" and it works so-so in terms of spreding files IMO.

Merci de votre coopération.