URGENT....144 hour visa question.... does the amount of time I stay in the third region matter??

So sorry for the "URGENT" caps lock but I need to book a trip in the next hour or so to Shanghai

I am going to fly London > Hong Kong (50 minute stopover) > Shanghai

Then within 144 hours I will fly

Shanghai > Doha > London

Does the amount of time I stay in Doha matter? There are two options... one with a stop over for 90 mins and the other with a stop over for 3 hours 30 minutes.

My understanding is that it doesn't matter and I can take either option?

It's so complex!!

Thanks

Ben