#but to me the fact that he did all that to preserve ocxy’s writing forgives the questionable aspects

[foolbehavior]

I definitely agree that Badeni’s tattoo plan is convoluted and has a high risk of failure on multiple fronts, but I think done more in-service of concluding his character arc. 

Badeni’s story is deeply tied to Ocxy (and Jolenta to a lesser extent), and formulating a plan like this proof of Ocxy’s impact on him. It hammers home one of the main themes of Orb; of how the idea of a moving Earth can dramatically move people as well and the power of shared connection. Badeni—a man seemingly immovable in his mission of proving heliocentrism through independent research and concrete scientific evidence—ultimately forming a plan entirely dependent on trusting in people and the power of inspiration/inherited will, while still maintaining his flair for the dramatics. It’s pretty poetic to me.

That being said, though the result of his plan is the same as simply leaving Ocxy’s book behind, I think there are also a few practical, non-character arc reasons he may have chosen this method of delivery:

Badeni is explicitly trusting Grabowski with the fulfillment of his plan

He knows Grabowski has an interest in the secular (re: the poem), thus may be more open minded to these ideas.

He knows Grabowski is a compassionate man and it’s much harder getting rid of 60 people vs burning/ignoring a book. Hostages in a sense, as you also mentioned, but their efficacy as hostages increase because he’s targeting Grabowski specifically.

The convoluted nature of his plan is a trial of sorts. If Grabowski is willing to listen to his letter, follow the beggar, and not run away, he’s likely to go all in.

Like how he hooked Jolenta through her curiosity, or how Hubert did similarly to Rafal.

Since Grabowski is very aware of Badeni’s prickly, bad personality, him trusting other people may also be a sign to Grabowski of the depths of importance the information holds.

So willingly trusting others must mean it’s something Badeni would change his principles for.

Badeni wasn’t planning on leaving anything behind in the first place, so he was already staking it all on small hope.

If he’s going to leave something behind anyway, might as well do all he can to hide it and he’s a man that doesn’t do things halfway

Similar to your point of audaciousness, leaving the tattoo heads creates a stronger legacy.

Even if Grabowski fell through, if the rumours of tattooed heads reached the right people it would be intriguing enough to pursue.

Perhaps he thought leaving a book behind, especially one simply written, wouldn’t be inspiring enough to chase down.

Classism and social standing.

Ocxy seems to be the only one consistently caring for the beggars.

Badeni was probably trusting in the fact that the beggars would have no one to tell and that no one would care about them to notice any changes.

Badeni also could have been checking in on them before things went to shit or by having Ocxy visit, he instills in them a sense of being watched (despite Ocxy being unaware).

However, I’m more trying to justify Badeni’s actions rather than fully understanding them. As you said, we can only guess based on the limited info we have. Only Badeni know’s what Badeni is thinking and unfortunately the man himself is dead. But it’s fun to think about…

Ok, maybe a controversial opinion, but I don't understand how Badeni's tattoo plan was in any way clever or practical.

Functionally, how is it any different from simply making a paper copy of Oczy's diary and hiding it in a safe place, then leaving behind directions to find it? If he trusted Grabowski enough to lead him to the beggars (making the assumption that he wouldn't report the blasphemous tattoos to the church), then I'd say he could equally well have left the entirety of Oczy's diary with him directly.

Worse, tattooing the pages on 60 different people causes a bunch of unique problems that a paper copy doesn't have.

Firstly, life expectancy wasn't exactly fantastic in those times, especially for a beggar. By the time Grabowski discovered them, half the pages could be missing from them dying — or hell, just moving to a different slum. I'd say it's very lucky that all of the people Badeni tattooed both survived and stuck together long enough for the plan to work.

Secondly, that's at least 60 people who have witnessed/experienced Badeni tattooing something weird on their heads. They may not know how to read, but they should have at least some idea of what writing is. So, again, it's an immense stroke of luck that none of them, at any point, got curious or suspicious enough to go to a clergyman and ask "hey, what the hell did this guy write on my head"?

And remember, that's 60 people we're talking about. Whatever chance one of them has to accidentally or deliberately reveal the plan — multiply it by 60. Plus, if even one of them was discovered, catching all the others would have likely been fairly easy for the church.

So... what exactly was the point of the whole plan? If you think about it, it's an immense amount of work for seemingly no reward. I'm genuinely curious what Badeni thought the advantage was in doing things this way.

[2025-01-15 EDIT:]

On further reflection, the only two possible reasons I can think of are:

Badeni was hoping that his sheer audaciousness would create an emotional effect on whoever finds the writing. The plan was proof of his devotion to the cause, and a plea for the next person not to squander all this effort. Though I seriously doubt this would be enough to sway anyone devout to the church, so it's a bit of a stretch.

The 60 tattooed beggars were essentially hostages. Badeni was expecting that if the church found them, they would be accused of heresy and executed. So he put 60 human lives on the shoulders of whoever finds the writing. Reporting the tattoos would mean condemning 60 people to death, which I bet even devout believers would hesitate to do.

But these are just guesses based on imperfect information. If the beggars explained how they were unwittingly roped into the plan, maybe they wouldn't be executed. So it's unclear if they'd even work as hostages.