no mars, it cannot be done just with that, because you cannot change the limit.
anyway, let's say you want max 10 downloads from 8AM to midnight
[download]
{.if|{.and | {.{.time|h.} >= 8.} | {.{.count downloads.} >= 10.} /and.}
| {:{.disconnection reason|sorry, retry later.}:}
/if.}
macro "count downloads" will be available from next build. (some variants are already available)