I'm really excited too and I'm encouraged by what you tell us of Rumour's behaviour, temprament and personality. I think that Vera raises her pups in a loving and unstressful environment where the pups are allowed to socialise with other dogs of all ages.
Not sure the time change difference from Serbia to where you are. It's significant for me. Rumor did need a couple of days to adjust to her new schedule.
Also I wonder if Gelert will know any English? I'm sure Vera has had to teach him some things and it probably wasn't in English.
I have no doubt he will adjust quickly and love his new life.
If he is anything like his sister, he'll be a busy, almost relentless pup. Very inquisitive, fearless and so smart, it will amaze you. My advice is keep him busy and don't take your eyes off of him. If there's is something new to him, he'll have to check it out. We all know puppies don't know it could be a real bad idea. We don't want to see you in the naughty puppy thread.

Now get your camera ready cause we want to see lots of pics! And take notes cause we want to here all about the start of your journey together. This will especially fun for me having a litter mate! Can't wait to swap stories of the siblings!

again and safe travels!
Just can't wait for the update!