[Liffer]

Wow, that was a quick and thorough answer! Thank you :)

I think that I for the time being can do a weekly review on all of my projects but will absolutely think about spreading them out if (or when?!) they become too many to handle all at once.

I just tried the change settings-link that you provided and used the value 1d hoping that it would give me a default of every 1 day and it seems to work :)
Also I found out that if I enter review mode and there is no project to be reviewed, the info in the bottom left corner tells me the status of the default review interval! For me it now says "Last Reviewed Today
Review Every 1 day
0 unreviewed projects"
Before I changed it it stated "Review Every 1 Week".

Perfect that the value can be seen in the ipad version, even though the way of changing it is not very intuitive.