Okay, the trip is over and it seems i've found what I was looking for.

I got regular Schwalbe Marathon tires in size 622x47 and used them together with puncture protection tape. I didn't go for Marathon Plus as I've read quite many opinions that due to it's extra protection layer it is too stiff and doesn't work well on the wet roads. No problems with my setup plus it saved me few euros. Not a single flat tire occurred.

In general I am satisfied with the choice. We had almost all kinds of road/offroad surfaces on the way. There were only two types of road conditions when it didn't work well: muddy wheel tracks on forest unpaved roads and dry deep sand. For the former conditions some side profile would be very helpful, for the latter ones - nothing reasonable would help i guess. But since we had these surface types very rarely I enjoyed these tires very much. I would probably get Marathon Extreme for a long rainy trip on forest roads. For all the rest of occasions I think plain Marathon would be good enough.

Just FIY, total weight including bike and biker was around 160 kilos and 28 inches wheels with these tires gave very smooth rolling on some really bad roads.
Here is the picture of the full setup (I myself needed such when deciding which tires to buy):