We have the x20e. Agree on the small black tank size, have to carry a tote on longer trips. Regarding the bunk end mattresses, we tried memory foam but it was too annoying to roll up after every trip, we ended getting some self inflating sleeping matts. They are great to slip under the bunk mattress and are easy to pack up.
2013 Jayco JayFlight 26RKS
2013 Ford F150 Ecoboost FX4
2003 Coleman Bayside / 2011 Jayco Jayfeather X20E -- RIP
2012 Tacoma Sport DCSB / 2013 Tundra SR5 - RIP