I belive that the packet adjuster is just for what your sending speeds here is the help text from it
Packet Size is an important setting. If you have it set to low (512) transfer speed will suffer. If you have it set to high and you have a lot of packet loss then you will also experience reduced transfer speeds. Usaully a setting of 2048 or 4096 is optimal. One very IMPORTANT thing to note is that the packet size has a direct impact on the maximum speed that can be achieved if using bandwidth limiting. You can figure it like so.. a packet size of 2048 will impose a top speed of 20kbs per send, 4096 will impose roughly 40kbs, and 8192 will impose roughly 81kbs.
Also you will need to set your per send DCC speed ( At least this is what I have done ) then restart your script as I am not sure the adjust timer is changed until you re start that connection to the network your on. Here is also some information on the DCC Manager
http://www.ircmadeasy.com/Inv.DCCManager.htm