I use "gz" on the name as a crutch to remind me that I used the "-z1"
option. Just as I and others will use ".txt" on their files names to
denote text files, even though Linux has no stinkin' Windows registry
to contend with.
On the ".000" front, I think I understand what you are doing. You are
numbering the chunks such that you can burn them to CD's.
Compromise: If the command is not called that regulates the chuck size
(such that they can fit on individule CD's), DO NOT add the ".000"
(I am backing up to 200 GB removable SATA drives.)