The following is a list of "du" (disk usage) from the A/UX 2.0 Root system, which tells the size of each directory in 512-byte blocks.
/*UNIX* 2900
/bin 5122
/dev 38
/etc 12874
/shlib 458
/usr/bin 8926
/usr/adm 28
/usr/catman 6218
/usr/dict 410
/usr/etc 1928
/usr/games 1400
/usr/include 2882
/usr/lib 12394
/usr/spool 448
/usr/ucb 3296
/lib 4464
/mac/bin 4594
/mac/lib 7344
/mac/src 504
/mac/sys 6238
-------------------
Total 82,466 blocks
If A/UX 2.0 is purely used for NFS purposes only, it might be possible to squeeze the size and fit it on a 40MB disk. However, it might take some time to go through each of the files and/or directories and determine which to keep or to remove.
In general, a lot of files and/or directories like /usr/catman, /usr/games, /usr/dict, /mac/src, may be removed.
The default Swap size in A/UX 2.0 is about 18MB. 14MB was the default swap size used in A/UX 1.1.1 and before. This increase is mainly for A/UX 2.0 MultiFinder activities. If you do not have many Macintosh applications and/or specifically A/UX applications like C language compilations running on the system, it may be reduced to below 10MB. Furthermore, if you have plenty of physical RAM, 16MB or 32MB for example, you may reduce more swap space.
Again, this is still the "It depends..." type of question. We can't give an exact number on the size of Swap area and also, which files/directories should be kept or removed. You probably need to play the "try and error" game to knock the system below 40MB.