How to describe essay formats?

Hello everyone,

I have to assign an essay to some students who struggle with English.  I would like to be able to tell them the Chinese words related to page formatting if need be.  Below is a list of related terms followed by my incomplete (and possibly erroneous) translation of them.  Do any of you know how to translate the missing terms?  Any other corrections?

Essay format:

• 2.5 to 3 pages
• single-sided
• A4 paper
• Helvetica or similar Font
• Font size: 12pt
• Double-spaced
• 2.5 cm margins

文章格式：

• 2.5至3页
• 单面
• A4纸
• 赫 尔维蒂卡或者类似的字体
• 字体大小:(don't know)
• (don't know)
• 2.5厘米页边空白

Note: I'm especially interested in the best way to indicate '12pt'.  When I use Chinese computers, I notice that there are two font size systems.  The one that is listed first in the drop down menu is the specifically Chinese system.  (I hope this makes sense.)  I wonder which Chinese size is the equivalent of 12pt?

Thanks in advance.