As far as I know, Prince does not use any of the existing HTML engines (Chrome, Firefox, IE, Webkit, etc). In order to develop HTML templates that will be converted by Prince afterwords, is there a kind of Browser that reflects changes in the code as you go?
Do any of the existing browsers can be used to preview the resulting page that would be closest to Prince native engine?

We try to maintain consistency with browsers, but none will be exact, and even when the layout is the same there can be differences in font metrics as PDF is resolution-independent. Perhaps the only long-term solution is to have a browser based on Prince!

Yes, that would be a perfect solution. Do you plan in the near future to develop Prince browser?
In the current process we regenerate an updated pages over and over what extends the development time and brings a bit of monotonous work ...

It would be nice, but unfortunately takes a bit of work to get right.

Thanks for your answers!