I meant that in the options for speed, where you choose "cable," you can also choose "modem", T1, T3.

In Options->Uploads->Basic->Upload Bandwidth move the slider to a % that works for you. The range of the slider changes to match likely ranges for each of the speed settings.

You can call your ISP to find out what your rate is, or go to a place like http://www.broadbandreports.com/tools to test your upload speed.

The number of upload slots doesn't affect the total bandwidth for uploads--they just share the % you set.