Re the pdf..... without overtly saying so, I think they are referring to the peukert effect...... so if you run the loads concurrently you will need a larger starting capacity to make up for this effect... this table for L16 battery says it all really.
For a 48v system:
At light discharge we have 460AH available useful capacity if we keep under 250 watts......., and say with all the gadgets running together ( eg 6kw or so), we have only 135AH capacity....and every where in between makes the 2:1 look about right ( wild average thing) that Xantrex alluded to.... or put another way, light discharge can do 3.5 times as much work as a heavy discharge can do... so if you can stagger the loads... good, if your victim of human nature, and ignore your advice and run everything when ever you want ( eg... wife )... then size accordingly.
Interestingly, my electric hot water uses 80ah/day@50v...2400w element... so 50 amps if I can use a lower wattage element ( arrived yesterday), compared to it's normal battery discharge, it will be less of a drag..... if I could get it down to say 240w... ie 5 amps....I get the water heated for near free ( comparatively)... need very good insulation around it too, and running near round the clock .... but will be an interesting thing to try.
................oztules