i already answered this, the first exploration is guaranteed to give new tablets, just gotta save scum.

Save scum means you go back to a previous save to change an outcome. This VN has a global save that keeps record of certain things you've done throughout ALL your playthroughs, you don't need to get the tablets in one go. You can acess from the main menu all files you've gotten from each like the image below. 

What i'm telling you, is that the code guarantees that the first day of exploration gives you a new tablet you didn't get on your global save yet. So save before you do that, get the reward for the day, then go back and load that save. This only works on the FIRST day, so don't advance beyond that. The code will not ensure new tablets after , going all the way to Ch 18 is just a waste of effort. I don't remember what chapter the first exploration day was, but i would say it's between Ch7-12.

nothing for now, probably something for a later update.