Deadlinless WUs client can't get work, normal one can?

[Joe42]

I'm re-doing all my fah clients as i had a bit of a mess before and wanted to change a few things, and now that the competition is over i needed to change the user id anyway.

I've got two normal clients, set to low priority rather than idle, machine id 1 and 2 for each core. These are working fine.

Then i've got 2 backup clients. These are machine id 3 and 4 (should they have been 1 and 2?) and they are set to deadlineless wus and are set to submit wus in batches. They are also set to idle priority to keep them idle while the normal clients have work.
They are both getting errors saying they can't get work, but the normal clients are fine. Is this because they use a different server and its down?

I'd also like to know a little about this 'submit wus in batches' thing. How big are the batches, how does it work?

If i start leaving this machine on overnight it won't have an internet connection, so it will work on the backup clients when its finished the normal ones. However, i don't want it downloading 10 wus and not submitting any until its finished them all, as this could take months if it only does a bit each night. Will it do this?

Thanks