We now figured it out our selves I think. Via fontsquirrel you can upload a font (make sure you own of use free licence) and have the tool directly creaste an css file in your created package. That css (multiple declarations to support all kind of devices and browsers) file contains the code you can add to the frontend.ss of the theme you want to use it in. Then for each page where you like to use that font only for H1 simply add a piece of code at the start looking like this: t t-name="website.NAMEOFPAGE"> When you now add a buildingblock to that page and add H1 text in that black it is in the custom lettertype. Any H1 text on other pages will still be original font. We are pretty much there but still need to fully validate above method. Maybe good to mention that a lot of web safe fonts are already delivered with Odoo (I write this for noobs like myself) so without adding thing to your CSS file you can already choose a many custom fonts in you pages by for example adding Creates COMIC SANCE in size 50 when choosing H1...this mentod you can also choose another one for H2 etc. Hope it helps somebody who encounters the same question.

FOR SOME REASON ABOVE COMMENTS MISSES IMPORTENT PARTS OF THE TEXT. I CAN NOT ADD ANOTHER POST TO THIS THREAD TO EXPLAIN HOW TO DO THIS SO IF YOU HAVE THE SAME PROBLEM SIMLY REPLY AND I CAN TRY TO HELP

how to embed custom font in odoo website(browser) ?font-type=Freight ??? how can i add my custom font in website? did you got any proper solution for that??