Get dual A/C's and 50 amp service. With 50 amp service you will not have to practice any energy management techniques. You can use what you want whenever you want without concern.
While the 50 amp cord will always be heavier, all 50 amp cords are not created equal. My OEM cord was heavy and stiff. I purchased an aftermarket 50 amp cord that was much more flexible. You can also by a 30 amp cord with a 50 amp connector that will connect to RV without any adapters.
Once you get used to 50 amp RV'ing you will forget all about limited 30 amp service.