Its not even about looking hard, level ten and level 5 should produce the same splits, but lower esistance means you need better technique to pick it up at the catch.
As a crew we will often sit on it for 40 minutes and try to maintain 1:54 ish.
Light ergs holding say 2 minutes at 22 st/m for 40 mins.
2K, anything below 6:40.
5k sub 18.