Calendar problems and limits

In a thread 'Times displaying incorrectly in Calendar' starting 29/6/15, 
I described a problem with EccoEE where new appointments could not be 
added.  After many helpful replies and several attempted fixes, I found 
that all worked OK in vanilla Ecco, so I switched to using that until -- 
yes-- I got whacked with low memory error messages.

Looking again at EccoEE, the Folder Window says that, for the 
Appointments folder, the Count is 16366 and the Max is 16330.  For all 
other Calendar folders, the Counts are lower, but the Max is always 
around 16330. Have I hit a limit in EccoEE?  Is there any way of getting 
round the limit?

If that's a real limit, presumably I need to delete some old Calendar 
data.  How do I do that in bulk?

A related but different question -- I have 2 Ecco files with some common 
Calendar data for 6 years from 2002.  I expect to delete all data for 
those years in the current Ecco file, but I'm not sure whether the data 
for those 6 years are identical or not (one file may have been updated 
and not the other).  Is there any way in Ecco to compare selected data 
from 2 Ecco files to see whether the data are identical?

Thanks for any help.

Lindsay Graham
Canberra, Australia