Glad you like it, I hope Holland is looking a bit better to
Frisia to will get a little overhaul one of the next days. So that Rüstringen and the other medival counties that lay where there was land back then can get into the game.
and one with a ship on the Elbe itself(its a bit bigish:glare
The Schelde (Scheldt) (in the estuary it splits in the Oosterschelde (Eastern Scheldt) and Westerschelde (Western Scheldt) schould be sailable too, at least upto Antwerpen (Antwerp).
Regarding the sea province, it would be better named Noordzee (North Sea) instead; the Waddenzee is the sea between the Frisian Islands and mainland Frisia (West Friesland & Friesland) and Groningen and most of that sea province is the Noordzee (North Sea) and not the Waddenzee. BTW the inland sea, used to known as the Zuiderzee (Southern Sea).
Regarding Frisia/Friesland do you mean just the coast line or will you turn every Frisian Gau/Gouw into a province (IMHO that might be a bit too much, even all the Seven Frisian Sea Lands, not to mention all 20 gauen/gouwen)?
Finally have you changed your set up in Lotharingia yet, regarding Lower Lorraine/Pfalz/Lothier; you know that I added a ducal tier Pfalz and turned Lower Lorraine into a titular duchy of Lothier.