You have presumably found how to disconnect after transfers in preferences or options. This is in fact the best you can do and it can take hours or days for downloads to complete after dissconnecting. If a host has established a connection he can in fact carry on with different uploads starting, even though you are actually dissconnected from the network.
It is probably better to just cut off any downloads. Do what else you want to do and reconnect.
I know exactly what you are asking, and I would love to be able to finish the current uploads and switch off. Sadly it doesn't work like that .... unless I've missed something for the last year
BTW email addresses are strongly discouraged on the forums ... for your own good largely, as these are public forums and spammers can pick up on e-mail addresses and send you piles of junk. Hopefully too, answers on the forums help others.