we did a 4 car group but we converted the 7660 cable drvie system. We averaged 2 days a car and when you do your first learn trip in the open you will think-- what have I done! Very erratic and jerkey but then it will just float closed as pretty as you please. I guess we did this mod about 3 years ago with no calls except burnt contacts on the new pilot relays but we fixed that by parralling another set of contacts. If you are only doing one car I would try to get 3 days as you will get better as you go.