GEP, that sounds reasonable (the need for backup, that is), although paper backup for some things can be excesive. You have to carry charts for any diversion that might be expected. On an IFR flight to, say, Biggin-Berlin, that includes Southend, Manston, most Belgian IFR fields, Maasticht, several German ones... do you print all these?
Personally, I use paper charts for departure, arrival, and alternate; carry the electronic charts for the possible en-route diversion, and a paper airways chart (the last time I opened one was during the ATPL theory exam).
I still find flying an approach using a chart displayed on the MFD inferior to the chart on my kneeboard (EFB or paper) [other than SID and STAR, which in my mind are best flown with the route in the FMS and the map - not chart - on the MFD]