How do I setup this arrangement?

["Gerben Wierda" <Gerben.Wierda@rna.nl>]

I want to use \setuparranging, \setuplayout and \setuppapersize to do the
following:

1. Page size is somewhere between A5 and A4 (large paperback book)

2. In draft mode:
   - Output pages are magnified (<1 factor) to a A5 size
   - Two pages on one A4 landscape
   - Ordering simple: (0,1),(2,3),(4,5) (2 shrunk-to-A5 pages on one A4
landscape)

3. In final mode
   - Output pages are centered on an A4 paper with crop marks

I have tried to find information, but the orderings of \setuparranging do
not include this simple ordering.

G