Hello @1stepup61
The reason that I suggested the DC-4 was because:
{These references are from various parts of the material in my earlier posts}
Between 1946 and 1954, BCPA flew across the Pacific. However, BCPA was a post-war virtual airline. It chartered all the flights to Australian National Airways and their Douglas DC-4s.
Flights between the USA and Australia, are refered to in the following text, part of which specifically identifies the type of plane used, as the
The DC-4 {possibly with reduced passenger loading for such long flights}
{introduced in 1942 with United Airlines} pass cap = 44. Range = 5,300 km
Flight distance from Sydney to Hawaii is 5,100 miles (8,210 km)
{with island rests and refuel stops en route.}
Flight distance from Hawaii to Los Angeles is 2,556 miles (4113 km) in just one leg
{no refuel points between the two locations, Hawaii and Los Angeles.}
So the longest single leg would be from Hawaii to Los Angeles a distance of ~4200 km.
Douglas Aircraft Company
7. The DC-2 {from 1934, with Trans World Airlines} pass cap. = 14. Range 1,600 km
8. The DC-3 {from 1936, with American Airlines} pass cap. = 21 to 32. Range 2,500 km
Douglas DC-3 {below}
The first successful commercial propeller-driven airliner

The DC-4 {from 1942 with United Airlines} pass cap = 44. Range = 5,300 km
The Douglas DC-4 {below} a four-engine aircraft with tricycle undercarriage introduced {1942 with United Airlines}.

Suggested analysis.
The longest leg is from Hawaii to Los Angeles, a distance of Distance = ~4200 km
The DC-3 {from 1936 American Airlines} pass cap. = 21 to 32. Range = 2,500 km
The DC-4 {from 1942 United Airlines} pass cap = 44. Range = 5,300 km
At initial comparison, the DC-3 does not have, in standard configuration, the range to cover the distance from Hawaii to Los Angeles, ~4200 km. They could have reduced passenger numbers, and increased fuel load with auxilliary tanks. However, even doubling the fuel load, which I think, would have been unlikely in any case, particularly in civil applications, there would only be an outside marginal reserve of 800 km (possibly less with the initial take-off fuel load). I do believe that this arrangement, even at that time, would not have been acceptable.
The other option would be the DC-4. It has a passenger capacity of 44, possibly reduced on such a long flight. The plane has a range, in standard configuration, of 5,300 km, that would allow a margin of 1,100 km without requiring to carry additional fuel. This, I believe would have been acceptable. It is likely that the flights would not always have been near full passenger capacity at that time, such as they have been in more recent times.
If your great uncle was traveling in 1947, that would have been twelve months after the commencement of the British Commonwealth Pacific Airlines (BCPA) flights to America which were chartered to Australian National Airways and their Douglas DC-4s.
So the factors that I have considered are:
The longest leg distance = ~4,200 km
Range (in standard configuration) of the planes,
the DC-3 at Range = 2,500 km
the DC-4 at Range = 5,300 km {to increase the range, the passenger manifest is likely to have been reduced by one third, which would allow for 30 Passengers, even if the flights were normally fully booked to the reduced numbers}
DC-4 services commence 1946
The year of flight, I understand, was 1947
The four engines of the DC-4 would have allowed for redundency should one or possibly two engines fail during the flight.
I hope that the details match the information that you have.
Wit My Best Wishes
@HenryX