While wget remains basic, a tool called “aria2” is far more
capable. It can fetch many files concurrently. Each file can have
multiple sources (mirrors) with support for a variety of protocols
including bittorrent. Aria2 can set the --min-split-size, so very
small files do not get split and fetched in parallel parts.

In situations where a session starts a new session with nothing
(scanMenu=''), it might perform better to fetch prebuilt ISO images
using aria2 rather than traditional jigdo algos. It can split them
into many pieces with many mirrors specified. This would perhaps
reduce the overhead of establishing a new connection for each deb
file.

I believe jigdo’s performance would make a substantial improvement if
aria2 were used. At the same time, many mirrors could share the
workload. And if jigdo analyzes the performance of each mirror as it
goes, it could load-balance on the client side.