Not sure about resetting ticket number however I simplified the reporting for a client of mine by automating the printing of the work period report on work period close.
As far as X and Z as far as I have always understood X is a non resetting ‘current’ report which you get by viewing the work period report. Z is where totals are reset which is where ending the work period comes in.
A quick look at V4 I cant see an option for resetting ticket number, someone may be able to offer a sugestion however this is something you would have to check through your system as there is ticket ID and ticket number.
Ticket ID is a database key for tickets which will always go up and ticket number is a more visual number however you would need to take in to account that some features will use ticket number and it may also be used in constraints etc depending on your setup. Personally I wouldnt but thats not to say you shouldnt.
A quick search has shown a few relivent topics;
However emres first post says
Which is what I was trying to get at above, sounds like its likely to cause issues.