I have set up several machines with the Dnet client on dial-up connections.
Here is what you should do.
with the 463 client-
2>Buffer update options
6>Keyserver/client connectivity options
9>Dial-up detection
option 1 enables auto dial when the client is running out of new work
option 2 is "lurk only" where the client will detect a connection and initiate a flush only then. Under the scenario you described, this option would be fine.
Be sure to buffer enough work to last the client for an extended period of time. You can use the time in hours option to automatically set this.
Also, and this I have found to be important, set your client prefferred block size to 33. The client has a default limit of 500 packets, and at the default block size of 8 work unit packets will limit you to a max of 4000 work units, which may not last a fast machine for an extended period of time. The block size of 33 means that the clent will request packets of 32 work units in size which is best for the proxies, keyservers and stats boxes anyway.
As far as the flushing process getting in the way of normal Internet use, the client runs at the lowest priority, even for use of the Internet connection. The client does not seem to interfere with this in any perceptable way.
As for AOL, ver. 6 (and I think 5) will work nicely as I have described above. it will not work with ver 4 or below, although you can manually flush.
Hope this helps.
viz