Barrel length does NOT affect accuracy or stabilization.
The difference between a 24 inch and a 28 inch in velocity can depend on a number of things, for instance a light load of say 70 or 80 gr and a fairly heavy bullet in a sabot say 290 gr will burn all the powder efficiently in less than 24 inches so differences would be negligible.
While a heavy load of slow powder behind a light bullet say 150 gr of rs behind a 50/40 bullet of 200 gr would lose a couple hundred FPS.
and would gain from a 32 inch barrel.
There is no black and white here knowing the load and bullet would help though.