I did use Ulmont's converter and I have a program to edit the save easily enough once our game is converted. For the edits I was thinking much the same thing really:
-The Georgian culture in Spain and Africa needs to be changed for sure and I was considering making the EU cultures in germany the proper ones, where they haven't been converted to dutch or something else that is. So anything with a german culture in CK will get its area specific culture mapped from a vanilla EU3 setup.
-The tag switches so we don't have the Ukraine ruling in Arabia is an easy switch and while not necessary would be nice
-As for the HRE I never really considered it. Guess it depends on how we want to play EU. Do we want to just crush all the AI and have a few big nations or have them be a part of the game? I like the idea of having the HRE but only if we aren't all going on a WC attempt (which I might add I don't really intend on doing)
-As for the forts a level 1 does not appear in EU unless there is a Large Castle there in CK, which means you might not see much of europe get them before time runs out given the slow progression of tech in the game so far. I don't have a problem with this and don't think they should be added as they are easy enough and cheap enough to build and it reflects the situation we currently have in CK.
-I never gave a thought into the centres of trade and am not sure as to how to split it up. The fact that new ones can be built though could make this less important as other players split off from the ones currently under my control. On the other hand they probably give me a huge income boost as controller if I remember correctly but then that is one of the reasons I went for those areas in CK was for the income so not sure what to do (always hard to suggest ways to make me weaker once we convert

).
Those are my thoughts on things but we have plenty of time to discuss this still and there will be time when we are bringing in new players (hopefully) that might change things as well.
Anyway here is the last save game:
http://Blackmist.fileave.com/1338.rar