I agree with Bob. Wider is better and ditch the stabilzer jacks.
I also have the Bigfoot on my E450 chassis (its the system same as your.... my directions had both MB and Food E450 on them).
You will love the system.
2017 Axis / 25.4: Big Foot Levelers, Aims 1200 Watt inverter, Ceramic Window Tint, Full River AGM 6V batteries, Front Hellwig Sway bar / Rear Track Arm, Safe T Plus Steering Stabilizer, PD 4655 converter, Hard Wired Surge Guard, WEboost + WiFi Ranger, LED Headlights/Driving lights, TPMS, Surge tank, Tornado flush, Viair Compressor