[scribus] Font fitting best - style question

[Rolf-Werner Eilert]

Now this is a question to the layout professionals here...

Currently I am working on a PDF form which contains fields to be filled.

Our standard font is Syntax, but I would like to use some serif font for 
the PDF fields (to be able to distinguish I and l for instance and 
because it is better readable) in bold. And it shouldn't look too ugly.

Is there a style guide of some kind which has some tips how to choose a 
serif font fitting best in combination with a sans font?

For a first trial, I chose Times New Roman Bold, but it looks terrible 
with Syntax.

I browsed the fonts on my system, and I found the following looking best 
with Syntax:
- Linux Libertine O Bold
- New Century Schoolbook Bold
- URW Palladio L Bold
- Utopic Bold

But I am not sure if there is maybe something better. So thank you for 
every input!

Regards
Rolf