At the moment I can and have done this by modifying cc_config.xml and so far have managed this and a few other things without breaking anything.

It would be much more convenient to be able to change these values via the GUI. Especially on the laptop where the difference between my home bored band and the fastest place I connect is a factor of 40+.

Thinking about this further, is there any advantage to transferring more than one file at a time? perhaps BOINC should make the default just the one?

My thoughts would be that with the large zip files that CPDN produces then one file transfer at a time is all that most peoples broadband could cope with. However for projects such as SETI which produces upload files of anly a few k (compared to 50+M on CPDN) the ability to upload more than 1 at a time might be useful. Shame you can't set each project individually.

you can set the max_file_xfers_per_project>2</max_file_xfers_per_project - currently 2 on this box though as I have set the total maximum to one that takes precedence. I haven't worked out what the advantage would be in having concurrent uploads even with small files.

I haven't worked out what the advantage would be in having concurrent uploads even with small files.

I have had the following reply on the BOINC message boards.

There are a number of advantages, a couple are:
When the computer completes a number of tasks between each call for data, thus has a number of files to transfer in each direction - If one file stalls for whatever reason others will continue, whereas if a single transfer stalls and nothing else will move until that one either fully times out or completes;
Multiple transfers can better occupy the available total bandwidth, thus although individual rates may be lower the overall rate is higher;

Still a shame not to be able to change it via the manager though.