change rendering width, margin from top, font size and add scrolling ?

[druogury]

Hi,
the question is in the title ^^, and the problem illustrated in the image attached.
I would like to have a wider display, set the margin from top and the font size, and have something like scrolling in case the there are 'too many' lines to display in the slide.
How can I change the template file to achieve this ?

Thanks