Leigh, your numbers are about right.
How a given airfoil behaves (how much lift and drag and whether it stalls or not) is a function of only three things: airspeed, air density and angle of attack.
Note that "load" isn't one of them. We often talk about our rotors being "loaded" or "unloaded" at so many G's -- but that is a metaphor. Airfoils don't sense loads, they sense those three parameters, period.
A slight complication with rotary airfoils is that their AOA and airspeed are functions of BOTH RRPM and the aircraft's own airspeed. In particular, at a given RRPM, the retreating blade's airspeed goes DOWN as forward airspeed goes up, and its angle of attack goes UP as forward airspeed goes up.
If my Gyrobee rotor ran into retreating-blade stall on takoff, it was probably because I levelled the rotor to gain airspeed a bit early -- before RRPM was all the way up. This increased forward airspeed but decreased the autorational drive that brings up RRPM. I probably then hauled the rotor back to "pop" off (increasing both blades' AOA suddenly). This direct increase in AOA combined with the AOA increase caused by the relatively high airspeed was enough to make one Gyrobee's worth of lift, but put the retreating blade right at stalling AOA.
The disc loading had no direct effect on this process, except that it allowed the machine to get off the ground while flapping, instead of doing its flapping while still stuck on the deck. As Chuck points out, a retreating-blade stall is a retreating-blade stall, on the ground or in the air.