Heroic Polonaise is very advanced.
''This piece is more advanced than any Chopin etude, it's like a blend all of them. Requires incredibly stamina, incredibly hand and finger stability, incredibly clean sound, incredible playing. So it's not a ''memorize and play'' piece!'' ( a masterclass with Martha Argerich, 2011)
First of all you need to play something more smooth.
48/2 is a nice choice!