First of all congrats on this interesting and ambitious project. While I was browsing through map I found an error in tile rendering. You can see it here: http://www.openstreetmap.org/?lat=42.82&lon=16.331&zoom=9&layers=B00FTF
There is know problem with coast lines. There have to be “well connected”. If not, the preprocessing script fails to generate the appropriate polygon. It seems that this is what happens here. I will examine this area closer in the near future, because my Garmin map conversion tool uses very similar algorithm.
are you sure this is related only to connectivity? It seems to me, that aklso osmarender renders most of the islands incorrectly (and a tile around them), because all the islands in pgs are clockwise, as they should be counter.
for example: http://openstreetmap.org/?lat=69.8346&lon=31.6131&zoom=12&layers=0B00FTF