Zephyr BLE connection management

[OwainIncus]

Hi,

I have a bluetooth central app which connects to several BLE peripherals and am now working on fixing various connection reliability issues.
White lists and bonding are bring used and I am forcing connection loss via use of faraday bags.

I have questions related to connection management.

1) Use of bt_conn_le_create() verses bt_conn_le_create_auto() ?

On my initial scan of peripherals, I make my initial connection to the peripheral using bt_conn_le_create(); security level is set to L2 and the device is added to the whitelist.
On disconnects I call bt_conn_le_create_auto() to listen for whitelisted devices so they can reconnect.

Is a better schema to just do the scans, and add my peripheral devices to the white list. Then use bt_conn_le_create_auto() to connect to the white listed devices. When any peripheral is disconnected (callback); then call bt_conn_le_create_auto() to listen for the peripheral reconnecting?

Also Is it only necessary to set the security level to L2 on that initial connection; or must this be done on seeing each reconnection?
A similar question with regards to service discovery; must I only do this on the inital make of connection; or must this be done on each reconnection?

2) Use of bt_conn_ref() and bt_conn_unref() ?

Should bt_conn_unref() only be used when I am no-longer interested in a connection. IE seeing a deliberate disconnection? or should this be done for every disconnection I see even these environmental ones; where I hope to see the device reconnect?

KInd Regards,
Owain

[OwainIncus]

This looks to be to do with the connection reference counters.
If I remove the bt_conn_unref() from the disconnect() callback and just re'arm the wit for incoming connection with bt_conn_le_create_auto(); then I can merrily loose and regain the sensor at random and the connection is reconnected after each period of disconnect.

So only if it is a deliberately disconnect a peripherl should one do a bt_conn_unref()?

This may be answer to one of my initial questions.