OK, let's call it differential training. I understand that according to FAA I need only complex and HP endorsements (which I already have), but I need some practice in that aircraft. Costs are high, but they are lower in the US that almost anywhere else. I'm not interested in renting, just some dual time to get familiar with the aircraft.
I already found out that they are not common at all, that's why I created this post. All I found is a couple of operators and a very old post here, so I will appreciate any relevant info about it.