1.You originally asked about 1280 x 720 resolution (16:9). Obviously, 1920 x 1200 (16:10) is different. Both fovx and font sizes will be different between those two resolutions.
2.If you know how to post a screenshot, then why don't you do it, instead of asking half-questions without giving us enough information to understand what you want to do? 
3.The difficulty with making a mod for fonts.ini -- or even listing "good" font sizes -- is that they vary by screen resolution, font typeface, and user preference. There is no "right" way that will work for everyone, and the variety of screen shapes and sizes makes it nearly impossible to handle all possible combinations.
5.At 1920 x 1200, the fonts listed in the moddb tutorial should be pretty close. They were intentionally chosen on the small side in order to accommodate even larger screen resolutions.
6.There are not that many fonts to change... to scale them all by 10-30% takes only a minute or two. You can make the process even quicker by experimenting with one font first in order to figure out a "scale factor" that you like, then do the others.
Skip the crazy six-digit precision... two digits to the right of the decimal is usually enough... three digits for fine-tuning.
