I think the ability to lock a line would be enough. If they put all your suggestions it'd be too easy for us to always get 3 lines. So, I think this only one would be ok to implement
EDIT after some thoughts: i'm ok with it only if you are capped to do this line lock only once per journal and with the cost of 8, not 4. In this way, 3 lines will be statistically a bit more reacheable, but only after more effort from the player.
The minigame is supposed to be hard, so this must continue.