As said by @jjss49 , shorter is better, all other things being equal. It means less R, L, C to interact with the speakers. So, I suggest you try to borrow a shorter set of cables or buy them with right of return.
Many who go to monoblocks use very short cables, a meter or less. Possible in your case (at least for comparison)?
Both parts of "audible improvement" are hard to predict in someone else’s system; i.e., whether the difference will be audible to you, and whether you will think it an improvement. Not all differences make the sound better or worse.