To fit more onto a tape, I would suggest you use 'compress -H' to compress the data. Your initial find command is piped to compress -H which in turn is piped to the destination device
To read the contents of the tape you will need to use 'uncompress' which is piped from 'dd if' command and uncompress is piped to cpio
How you back up is your choice..of course. The test of any backup type is your ability to successfully restore it, both on the source system and on a replacement system if the source system ever fails.