Proxies are great, if you can use them properly but getting a list of decent fast working proxies is still a pain (especially if you are not accustomed to doing so). I download using Tor all the time but I don't use a webstripper like JDownloader. Tor is made for that, the average use of the internet. Public proxies can be just as slow or slower and many foreign proxies are required to log access or have filters in place (because they are from corporations who don't want their employees using the internet for personal enjoyment). I don't use public proxies very often anymore myself, just too much hassle for what they offer. I do use webproxies inconjunction with Tor but that is another story. If you could load a proxy list into JDownloader then it might be worth making one, otherwise Tor would probably be better for your purposes as they switch nodes from time to time. However if your filehoster blocks Tor, and some do, than making and using a proxy list is not a bad idea. Some proxies are as fast as your internet connection can go.
FYI:
Akiba-Online had a lot of problems with the Imouto sets posted here, one of the reasons they switched hosts (two or three hosts back, actually).