First of all: welcome to wikitree.
I am from Belgium, so I know the 'problem' of the Latin vs Dutch vs French versions of names very well. I settled on using the language of whatever is the earliest record for the 'proper first name' field, but I use the 'preferred first name' field if I have evidence of what the person usually was called. There's two reasons for this:
First, in the case of Hendrik, you know the Dutch version, but you'll probably come across people for which you don't know, because all available records are in Latin. e.g. Theodorus might be Dirk, Dorus or Theo. Anything other than the Latin form would then be a guess.
Second, using both first name fields makes it easier for other people to find the profile. The wikitree search is not smart enough to find Henricus if you search for Hendrik (or the other way around), but it is smart enough to look in all first name fields.
And as an added bonus, you'd be following the Dutch Roots guidelines :)