HIIT question

[BaconAndAvocado]

I aim to do 3 HIIT sessions a week, including one with a PT lasting one hour.

The other 2 I use Joe Wicks.

My question is would a 20 min 40/20 session or a 30 minute 30/30 session be better?

Obviously I'm exercising for a longer amount of time in the latter but with more rest time.

30 minutes 30/30 better- your heart rate is up for longer. And you can build it up to 40/20, 45/15 etc with time.

Thanks, I'll just go on for a bit longer for each exercise section.