Leakage check

Hi

I just installed a mini SPLIT system pipes and I am about to vacuum it.

As I don't have nitrogen I applyed air with a small air compressor the type we use to tires.
( using a refrigeration filter in-line).

I spread soap and saw some bubbles on connection.

I tightened the connection and saw no bubbles anymore.

The manometer read 87 PSI for 30 minutes and then drop to 84PSI.

1- If there is not bubble anymore at 87PSI, can I make sure there is not leakage ?

2- What is the better choice to flare a tube ? at minimum or maximum

I did it at minimum possible, almost even with the flare tool surface.
I notice when I do it too large the nut seems very hard to tighten.

Moises