The Ghost Rating system is hand calculated, but it doesn't have to be. Essentially, it is a system where each "bet" is a fixed percentage of the players current rating, and can be in fractions. The "bet" is not selected by the players. It could operate on the fly, automatically work for different variants, ppsc & wta, and account for draws.
Basically it is this:
Instead of the game creator dictating how many points for the game, the skill rating system takes 1/22.5 of the players skill-points for each game. This makes it more "expensive" for a skilled player to play, than a noob.
So, if a noob (with 100 skill-points) wants to join a game, it would cost him 100/22.5= 4.44444 skill-points to play. If a skilled player (with 1000 skill-points) wants to join the same game, it would cost 1000/22.5=44.44444 skill-points.
Once the game starts, there is a pool of skill-points which would be distributed the same as the current point system works today. Draws would be split equally. Wta games go to the winner, ppsc games get distributed according to ppsc rules. (I am not sure how replacements are factored in.)
The net effect is that more skilled players will gain very little from defeating noobs, but noobs will gain a lot from defeating a skilled player.
This system would be able to work in parallel with the current point system, and would have a different purpose. The current system limits the number of games because a player can run out of points, but does a poor job at measuring skill, but the skill-point system (more) accurately measures skill, but doesn't limit the number of games, since you can never run out of points.
P.S. There is a long mathematical explanation why 1/22.5 factor was used. But basically it prevents wild swings in skill-points, and allows a reasonable opportunity for noobs to gain skill points. A lower number might cause radical drops in skill-points for skilled players, and a higher number might cause too slow of an increase for noobs. My explanation is a very simplified description of their mathematical explanation.