Nice mod! I think having a good voltmeter, displaying tenths of a volt, is critical for understanding the charge level of your batteries. A shunt based battery monitor is probably better, but a good voltage display is the minimum requirement. The four light display that Jayco and most other OEMs use is worthless, in my opinion, because it doesn't have enough precision to inform you of battery health/SOC.
retired USCG aviator
2020 Jayco Greyhawk 29MV/2021 MINI Cooper toad