can you please elaborate more on the differences between the two examples you put? i do understand the concept but can you clarify it a bit so i can for sure know which one to use?
Both examples start with abc123.
The % tells it to use wildcard characters after that.
1,8 tells it to use between 1 and 8 wildcards, so the total number of characters when added to the 6 you already have will be between 7 and 14.
7,8 tells it to use either 7 or 8 wildcards, giving either a 13 or 14 characters password.
i tells it the wildcards are case insensitive.
n tells it the wildcards can be letters or numbers.
Also, is there a feature to save the password IF FOUND to a file so in case the session got disconnected for any reason?
You are looking for the autosave feature:
https://github.com/3rdIteration/btcrecover/blob/master/docs/TUTORIAL.md#autosave