No space between the cps
Start, finish or multilapstart do not count as a cp.
The direction of the cps does not matter.
Custom cps count as a normal 1 block cp (1x1 area), regardless of the custom cp's size. So if a custom cp is placed on the edge of the regular block grid, the custom cp counts for the building position it is most in.
e.g. a custom cp is 40% in 1x1 block area A and 60% in the 1x1 block area B, then it counts just as if there was a regular cp at position B.