I found that the very first challenge mode 'Intensive Treatment' was the best place to do this. There is 4 rounds and your combo means nothing so don't be scared to play it safe and spam
to have a counter ready. I also advise to using the bat claw (when you have the upgrade from story mode to have 3) by double tapping
as it will pull and temporarily stun 3 thugs instead of one, and double tapping
to escape danger (doesn't matter if you vault someone or just roll away).
Hope this helps!