Theres no harm in getting a 75 or even 100 gallon high BTU tank.
regular tanks are about 40,000 BTU my high output is 75,000 BTU 50
gallons. thats a lot of water. by the time i am done getting a shower,
dressed and go downstairs with the laundry the tanks burners are
shutting off, and my shower has the flow restrictor removed