It looks like you're right; my apologies for the bad advice.  I
remembered that all the startsb block numbers had been corrected (to
"2") in 4e but had forgotten about firstsb (and I'd initialised it in
my file servers to "2").  firstsb (if non-zero) is primarily an
optimisation and it depends on the specific jukebox and on time, so in
either /sys/src/fs/emelie/9pcfs.c or /sys/src/fs/sony/9sonyfs.c,

	conf.firstsb = 13219302;

is presumably wrong (I'd bet on 9sonyfs.c being wrong) and could be
deleted or changed to

	conf.firstsb = 0;

Also, /sys/src/fs/words should probably be amended to advise zeroing
firstsb in the spun-off subtree's 9*fs.c.

I noticed just now that conf.wcpsize is not used in 4e; it was used in
3e in /sys/src/fs/port/worm.c in wcpinit(), but worm.c is now gone.
So all those

	conf.wcpsize = 10;

lines in /sys/src/fs/*/9*fs.c and

	port/main.c:	conf.wcpsize = 1024*1024;

can be deleted.