For now I would like to say that it takes too much inventory space, could it use any scripts to allow writing what you want when you place it, it would consume the text plates you have to write stuff, and would only less or equal number of characters than text plates you have in inventory.

The best solution I can think of right now is a setup where you could make a 'Small Iron Blank' plate. While you're holding it you can choose a letter, and when you place it gets swapped for the chosen letter.

that could be a good way of doing things.

I've tried and I could say that the Gui is gorgeous, I know that each letters are needed in case they are crafted and built by bots but could it be moved in a inventory tab reserved for bot stuffs (things that a human would never use by hand)

At some point yes, but I have to figure out how to do that first.

I just moved everything into a Text Plates tab. The Blanks are at the top so you don't need to search for them.

I've think about a way to cleanly implement this without using so much space.

1) You use constant combinator without slot and without cable port.
2) When construction bot build things they also copy the ghost configuration, so the one in blueprint.
3) It's possible to get and set the configuration via scripts.
4) When a ghost is placed (manually or via blueprint), it's detected as a on_built_entity event.

So what can be done is:

1) Allow a slot in the blank plate.
2) Put all extra letters as signals
3) When a plate is destroyed, transform his ghost as a blank plate with his letter put in the slot.
4) When a blank plate is placed by a robot, transform it to the letter defined in the slot. If that a letter of another type, use the letter but not the material and the size, if something illegal, do nothing (keep it as a blank plate).

It seems to be working well so far. I quite like how the ghosts have a little letter on them so you can see what they will be.

Now this is a great Mod!
Is there a possibility to see the letters on the map or to write in the map?

It seems to be working well so far. I quite like how the ghosts have a little letter on them so you can see what they will be.

Not specificaly wanted but great, that tipicaly an unexpected feature ...

Getting the text on the map... it would have to be something sub-pixel. Maybe the station text, the markers used for vehicles, or maybe the alert icons like items missing.

For my part, I think this would be too much to add text on minimap, stations does the job correctly in vanilla, the only things problematic is that it's needed to place a rail then a station and finally remove that rail and that minimap text-paltes are registered as stations.

So you only have to make a "station", no great graphic (only a block), 1x1 big and it would be best then this tile is walkable like a floor. :-)

Sorry I'am not a modder (I am to stupid for that...) so I don't know if this is easy makeable. I'am only a gamer, who often search (and don't find) certain buildings on the map. And then I always think that the developer should integrate a writable map.