Hi !

I search in eastprussia at the area of morag ( german : Mohrungen). It´s about 80 km from Heiligenbeil.My favorite page for eastprussia :
kartenmeister ( = map master).com
http://www.kartenmeister.com/preview/City.asp?CitNum=7396
I hope the link works, the page is multilingual.
There is a person searching in this area : Manfred.Boettcher@gmx.de, he has added his adress to be contacted.
and :andkor@aol.com
http://www.kartenmeister.com/preview/City.asp?CitNum=7397

Leysuhnen belonged to the civil register of the town KARBEN.There are some register for "Karben" filmed by LDS/Mormons.Give place : Karben . Karben was in eastprussia/today Russia.The second & third towns are equal.
http://www.familysearch.org/Eng/Library/fhlcatalog/supermain...
If you get no results, I can maybe help you with land and propetery.This is filmed in statearchiv Göttingen/germany. I can call them ,and ask if they have any additional documents of this area.The tax lists are filmed in Königsberg,today Kaliningrad/Russia.

Good luck !