Hey Harry,
glad your post could be recovered. Scilab is indeed a very powerful application and as such needs some training to get used to. But I would say it is totally worth it, especially in your career as a mechatronic or for private hobbies. :-)

Regarding your questions, right now I’m not on PC with scilab installed so I can’t test it, but my thoughts:
1. “thin lines”
Could it be that you mean a grid? If so you should check out:
https://help.scilab.org/docs/6.0.0/en_US/xgrid.html

2. infobox
Unfortunately there is no way (yet) to tell the infobox to have it in the “lower left”, instead I had to hardcode the coordinates:
> xstring(1,0.1,infobox,0,1);
In this case 0 / 0.1 – so if this is outside your axes boundary, you will not see the infobox. You can check this by zooming out in the graph window. To fix it, try changing the coordinates in the script.

3. PDF
Need to check this, might be a bug (or feature) of scilab.

Hope this helps and feel free to ask again. :-)
cheers
richard