There you go again, suggesting the stunningly obvious and correct answer!
Thanks.
The notion had vaguely occurred to me but I was thinking it would slow down both backups given that Mac "P" would be writing to both ext HD partitions at the same time, and that its CPU would be executing SD! locally plus dealing with the net traffic... so I kinda pushed it aside, mistakenly... I'll give it a try though! I sure need to upgrade from WiFi 802.11B to 802.11G (so I'm closely watching what happens with the MacBook Pro)
