I got the impression that what was went were quite large stones - as i said worth removing even if the builders did not clear the ramp.

You have a choice with ramps - too long or too steep.

The ramps that wrap around the pyramid is the most logical idea for me. They are neither too steep or too long. The length has to be no more than enough to give a good "start" to hauling the stones up the pyramid, and the steepness can be controlled by the pitch and number of ramps around the building.
The use of large stones in the construction of the ramps is not feasible, IMHO. There would be too much time and effort in building and removing the ramps. If they were built of gravel/sand/small stones, it would be much easier to do both, and therefore use much less time.