Backup and restore

http://www.7-zip.org/ <- what i use vs winzip. 500 megs of text files = winzip an hour or longer.  7zip = 10 minutes. it seems like.  right click in "file explorer" of windows = fast options of basic formats.

.tgz   vs  .tar.gz    the double compression may cause issues.  and folks not understanding   (same thing just different way of showing it. as far as i know?

.tgz = tar first, then gzip

.tar = tar 

.gz = gzip

.tar.gz = tar first then gzip

for 7-zip = adding to archive (via right click) and choosing tar then click ok, then repeat but choose gzip next then ok  and then if need be rename file extension?