u only need the 400 gauge on the tank. Since u will be more than likely running the bags at 100 or less it won't effect u but if u are shutting off the tank at 200psi and use a 150 psi sender u will get EEEEEEEEE as a reading until it goes below 150.
Thanks for the info. Thats the answer I was hoping for. I could care less what is going on in the bags over 130 psi I just wasn't sure if they would error out and need to be turned off then back on. I have only used analog gauges in the past and I didn't feel like running 1/8" airline in my car.