Layout, HTML and iPad

[Eb00kker]

Hello and thank you for this forum.
I am a programmer with good HTML understanding so sigil was a great find when a crazy 1000 page handwritten book "fell" in my lap.
I would appreciate if you could resolve few conundrums which puzzle me and by the life of me i dont know how to get around them...

What is the preferred CSS settings for the margin for optimal page view?
When creating long HTML tables, how do you determine Row sizing and make it not appear half broken through the page?
In fact, what is the best setting for table layout? Pixel, em, percent size?
Why can't I center a p element ?

These may be iPad related issues but I don't want to double post. I'll move this thread if necessary.
Thank you very very much for your help.