Please note: I had a delay at KM12 due to being held up by the rangers at the park entrance station. This delay cost me several hours, and if you look at the GPS track from my watch you can see that I had to get in a car, head ~20kms up the road to the ranger HQ, before driving 20km back down right to where I had left off and continuing the mission. The 104km distance of course does NOT include the extra car mileage but is just the pure circumnavigation + summit. The 47.5hrs DOES include the delay as it didn't seem fair to me to stop the watch and then restart it for a non-continuous mission. The Aconcagua park rangers certified my 360 time as 41hrs and 3mins, but this is 'only' for the distance from the Punta de Vacas ranger station (park entrance) to the Horcones ranger station (park exit) which omits the ~20km of road that allows one to close the 360 circle... I figured the cleanest way of recording the FKT is to say it's the full 360 (104km) with a time of 47.5hrs.
As far as the support question goes: I had preplaced caches on the mountain for a self-supported mission and I had no pacers or designated crew, but! I had gotten to know the seasonal staff on the mountain well enough that by the time I ran the 360, I had friendly faces offering me drinks and hot food at both of the Aconcagua base camps; there also was a local guide on the upper mountain (unexpectedly - I didn't know in advance that he was going to be there) whose presence gave me a lot of psychological support... so in the end I'd probably classify this as a supported FKT.