The colors of Federal Yellow are almost impossible to tell apart, other than the "mustartd yellow" color they used in the late 1990s on newer Cub Cadets. If you've already painted a 61 Farmall Cub, and are happy with that color, then I'd use it on the Cadet. They would have been the same color yellow.
The white color is a little more telling. The correct white color for 1961 through 1967 would have been 901 white. It's hard to find, and you almost have to get it mixed at NAPA or somewhere. The 901 white has an olive tint to it and is definitely visibly different when next to 902 white and 935 white. Most, people get 935 white for their restorations because it is still readily available, but it was not used on Cub Cadet or Farmall Cub tractors until 1970. It is the typical creamy white that everone associates with IH products. 935 white is pretty darn close to 901 white, and you'd never know the difference unless you actually had 901 white next to the 935, in which case you would see that 901 is visibly more olive color than 935.
902 white was only used on 1967, 68, and 69 tractors and is almost "chalky white" looking and MUCH more white than either 901 or 935. Rarely does anyone ever find or use this color, and you would have to have it mixed special as it's not available from CaseIH.
Here are the three:
