I think that the simplest accurate method, that Sir Isaac would approve of, is to use s = ut + 0.5*t^2.
So, if V0 and Y0 are values from the previous tick, and g is the pixel gravity:
Y1 = Y0 + V0*dt + 0.5*g*dt^2
V1 = V0 + dt*g
(ie the exact method from the spreadsheet linked above). Any other morbid will introduce different errors...
Raycast is required to prevent tunneling and high speed / low fps problems.