Server priorities, server subsets and direct bodies' downloading

Server priorities
   There is an alternative (maybe better) description, please look for it here: Server priorities

   Every server can be assigned a priority in the range 1 (lowest) - 128 (highest) with or without the 'strict' flag. Suppose an article can be found on a set of servers. If all servers in the set with the highest priority have their max number of tasks running - the behaviour will depend on the 'strict' flag, if it is set at least for one of the servers - the download will be postponed, otherwise a server with highest lower priority will be used etc., i.e. the 'strict' flag prohibits using a server with lower priority while there is a chance to download the article later from a more preferred server. If a server exhausted all its retries - lower priority servers will be used in any case if necessary. Within a group of servers with the same priority - the fastest server available will be used.
   The option is located in edit menu -> properties -> servers pane.
   Note: The 'minimize overall downloading time' option in the tasks menu should be unchecked, otherwise the option will be ignored (it should be unchecked also for getting complete partial messages faster, it makes sense only for batch mode).

Server subsets
   Servers can be divided into 'Subsets' (it could be called a group of servers, but the word 'group' may be misleading, associated with newsgroups).    The user can define maximal number of servers and/or tasks that will be run within the subset. A subset can be ignored, then the subset servers will act as usual servers.
   An example describes the situation when a Usenet provider limits the number of servers at a time (connections per servers are defined in properties->servers as usual), although the subset feature can also work when providers limit the number of connections across their servers (or even both).

   Create a new subset through invoking 'New server subset' from the context menu:

   In our example the server provider restriction is at most 2 servers at a time:

   Now select all related servers and drag them into the subset:

Downloading bodies directly without downloading headers - Message-Id direct
   The idea is to download bodies without necessarily downloading headers. With several (nearly) complete servers (to minimize the number of misses) one can download headers from a complete server and check the option for the rest of servers. The 'Strict' checkbox to the right of the 'Message-Id' checkbox prevents downloading headers for their subscribed newsgroups; when unchecked headers will be downloaded as usual, but also messages that are not in their headers will be tried.
   Another example when a server name resolves to several IP addresses and the user wants to maximize server utilization by entering all ip addresses instead of the server name; since the servers are mirrored there is no necessity to download headers from all of them; we can download headers only from one server and for the rest to check the message-id direct (strict) option.
   Also when properly used the option can reduce header bandwidth that is useful for payed servers with download limits.