found this link for the HE-177A3, but it quotes two weights and don't' know enough German to know.https://ww2aircraft.net/forum/threads/h ... imb.17209/
The lesser mass is 26 ton for a bomber with 16 tons empty & 31ton max. Bomb-load seems to 6-7 tons while max fuel is 13,500 L suggesting 10tons of fuel. The threads speak of 80% mass being the point were bombs are dropped leaving 1/2 fuel clean.
Top speed looks like 550kph or 340mph @ 7 km altitude. Using hp/weight the mass should drop from 26 to 21 tons @ 1/2 fuel allowing top speed to exceed 354mph clean @ 1/2 fuel .