I have used both Lignumis and Director's cut and I don't really see any differences. What is supposed to change between those? Requirements of wooden belts to be made into yellow ones? Some bio-processes with the gold seeds? I can't seem to find anything that changes stuff, though I haven't checked every possible recipe (but saw you mention biochambers in the description, yet haven't seen anything new in those between the base and director's versions)

The Director's Cut enforces mod settings and adds more mod dependencies. It has no additional content.
When I created it, I changed the defaults for the settings of the base mod to be more mainstream compatible. The Director's Cut enforces full telescopic recipes and adds all wood mods for the vanilla planets and space. There is a chance you already played like that before and therefore the DC doesn't change anything for you.

Oh, I see. So if need be, you can just disable DC and change config in mod options to, for example, turn off telescopics? I don't mind it but a friend seems a bit upset about needing wood everywhere. If possible I would guess that before those changes we'd need to remove all assemblers with recipes set to wood belt upgrades too, right?

You don't have to remove anything. The assemblers will just stop to use the wooden ingredient.
I made the two versions specifically for people like your friend.

Oh, and the answer is yes. Currently you can disable the DC and nothing changes until you go to the settings.

Thank you! Will give it a look and decide then