Unfortunately, anonymous proxy servers might sometimes be rather slow, and there is nothing we can do about that. The difference may not be glaring for people having a relatively slow modem access, and for them the connection may become even faster with some proxies; however, for those who have a fast connection, surfing through a proxy may or may not mean some loss of speed. However, the full version contains a large sample database of proxies and there is a chance that you will find a better proxy there. You must test all proxies, sort them by speed and use the fastest one as your default proxy (you can also find the fastest proxy for a particular website with the Check URL feature).
If you want A4Proxy to change proxy for each request, you should limit the number of proxies used with the option “Use [n] proxies from [x] position”. The proxies are counted from the top downwards. So, if you want to use top 5 proxies, you enter “Use [5] proxies from [0] position” (the top proxy is #0). The best strategy is probably to group all proxies between which you would like to switch at the top of the list.
You can also add more proxies with the Add Proxy command in the Edit menu in A4Proxy from the web pages devoted to the subject. There are many websites on the Internet that host listings of proxy servers, you can look for them using a search engine like Google or Altavista: enter something like “anonymous proxy list”, “public proxy” etc and you will have a lot of links. Be prepared, however, that some of the proxies you find will be non-anonymous or non-working. It is important that you check them with A4Proxy for anonymity and speed.