I limit my upoads to one per person and a total 5 uploads at one time. I occasionallty change this to 2 and 6 respectively. I share over 3000 files. I imagine the files I share are less popular than yours
(and I dont consider 1500 files to be a small share and I keep thinking I should cut mine down a bit). A large ammount of what I upload appears in others shares.
I rarely have a queue. Yes on occasions I am downloading from a host at the same time he is uploading from me and if he is having difficulties I might manually stop a couple of uploads to help him. The problem is ... that makes others unhappy ... they think well if this guy won't share why should I and it just has a knock on effect. You clearly are having a lot of your files redistributed, and if your freinds search for the files, they are more than likely to find them in a variety of sources, rather than just you. Then every one is kept happy!. I often choose 1 host to get a line of files from, and if things are a bit slow and I search for some of the files. I find them elsewhere and the download process is sped up.
As you say ... you would like to play favourites now and again, and you can manually but this could get others upset and they might just ban you. .... I have banned hosts for less
I allways un ban them after a few days though!
A final thought: I have noticed some hosts list their connection as modem, (when clearly it is something much faster
make of that what you will.