Honestly depends on you, but my recommandation would be that if you see youre strugling somewhere (like Bowsers in your case) its definetly worth practicing a few times. Most runners practice stuff they have problems with before they want to do runs (and can also warm up their fingers a bit). Still you should focus on your Runs and try to minimise the resets you have
For beginners, it's generally accepted that the best way to practice is to do full runs, as it will help you get more comfortable with movement in general and you'll improve your game overall. But I do agree with Arkani, there's no harm in focused practice on something you struggle with as a beginner.
it honestly depends on what kinda time you want and how much time you wanna spend on this game.
if you just wanna get a sub 1:20 and be done then sure you can just do runs, but if you wanna take it further then you absolutely want to practice IL's
