Dont think thats right?
Bit worried to have a go at this, but in the 1:1 case, the sail applies a 50kg load down, the halyard the same vaule to hold it up there, therefore masthead has 100kg of compression.
In the 2:1 case, the load required in the halyard becomes 25kg each side of the main, and another 25kg tension, so maybe 75kg compression?
Im ssure ScottiE or Ed will correct me if Im wrong.