(Hi Zengineer, No Bug/Suggestion - Earendel have close his section to write - if you dont like this text here, feel free to delete but i think it could help people).

Maybe it help some Gamer - if you thing the Textplates are much to small this could help you for edit the main mod:

Instructions on how to increase the font size - Your Factorio should not be running:
For Windows/Steam version, navigate to: C:\Users[Your Name]\AppData\Roaming\Factorio\mods

Make a backup copy of textplates_0.6.10.zip and save it wherever you prefer.

Open the file textplates_0.6.10 in the folder C:\Users-\AppData\Roaming\Factorio\mods and navigate to: \textplates_0.6.10\prototype\entity
Now, copy out the entity.lua (I've had bad experiences editing files directly within the ZIP archive, changes are often not applied, so copy it out separately!)

Open entity.lua (It's best to edit such files with Notepad++, but Windows Editor will suffice if necessary)

To be changed are in lines 21, 31, 42:
scale = size == "large" and 0.5 or 0.25,
scale = size == "large" and 0.5 or 0.25,
scale = size == "large" and 0.5 or 0.25,

The first number (0.5) refers to the displayed size for the larger font, the second (0.25) refers to the smaller font.

In our example, let's increase the size tenfold and change all three instances to:
scale = size == "large" and 5.0 or 2.5,

Theoretically, we could already save the file and copy it back into the Zip archive. We would already have a font ten times larger. BUT the Collisionbox/Selectionbox would still be too small. We would have too little spacing when "drawing" text - However, if you placed individual letters, it would work and have an advantage! We could now write where something already exists. For example, half in the water or over rails. Nevertheless, it would be better to increase the collision.

To do this, go to lines 77/78 and 89/90 Since we had ten times the size above, we also take this value for the hitbox:

    collision_box = { {-0.45, -0.45}, {0.45, 0.45} },
    selection_box = { {-0.5, -0.5}, {0.5, 0.5} },

    entity.collision_box = {{-0.9, -0.9}, {0.9, 0.9}}
    entity.selection_box = {{-1, -1}, {1, 1}}

We turn this into:
collision_box = { {-4.5, -4.5}, {4.5, 4.5} },
selection_box = { {-5.0, -5.0}, {5.0, 5.0} },

    entity.collision_box = {{-9.0, -9.0}, {9.0, 9.0}}
    entity.selection_box = {{-10, -10}, {10, 10}}

Now, save the file and drag it into the Zip archive where you copied it earlier - overwrite the existing file. Close all windows and start Factorio to test the two font sizes.
(It is important not to accidentally delete or add characters while editing in the editor - if something goes wrong, you have a backup)