Yes Eddy wa closer to the 6700 than the 4900, but likely around probably 6200 or so in his La Cueva area as the highest houses in the foothills area are probably the 6900.
Altitude wont change hemoglobin much. In fact if one is living and training at altitude without taking iron, their hemoglobin will decrease because the new red blood cells created by the increased epo (thought limited) from training and living at altitude will eat up all the iron stores one has. You can literally take near toxic amounts of iron while living and training at altitude.
Al Sal has his athletes eating it like candy when they are training at altitude as well as sleeping in their altitude tents.
The need for iron is increased ten-fold when an individual uses epo. Epo cycles are typically precluded by an intense iron loading phase, and not the basic ferrous sulphate forms either, individuals will use highly bio available forms in order to boost their iron levels high in a very fast manner.
I dont think high hemoglobin alone can get you into danger, except from iron poisoning, but that is VERY hard to do as I know several runners who had 18s and 19s and had no problems at all and their doctors were not either.
It is when the high hemoglobin, high hematocrit, and low resting heart rate are combined when an athlete can get into trouble. Many cross country skiing teams used to get up in the iddle of the night and do jumping jacks and calisthenics because of their epo use, high hematocrit, and low resting heart rates. Some that didnt in turn died.
I do agree with you that eddy was not a smart doper though. He should not have used at the olympic training center, nowhere did it state he was routinely monitoring his hematocrit level, which would be stupid and very dangerous. It said he did a "unit" of epo a few days before the tester came for a sample at the olympic training center. Epo is measured in international unit (IU) and it typically takes an average person about 3 injections of 3000iu in order to boost hematocrit 1%. so he did a unit? That will do him a lot of good...This shows eddy's stupidity, but anyone who knows him knows that he was very very stupid. He seriously lacked intelligence. You could often speak to him and just wonder if his brain was actually working. He was a greasy slimeball who would have made an excellent used car salesman because he could lie and get you to think he knew what he was talking about and actually gave a damn about anyone but himself.
You are absolutely correct that there becomes a point where there is a deminished return from the epo due to blood viscocity. However most athletes that use the drug are also using plasma expanders, hespan, mannitol, glycerol, saline, etc so they have the benefit of having the hematocrit of 55-60 but the fluidity in their blood of a 40-50.
Cyclist will often go to 55 and higher for their hct and then dilute down to 49 so they are under the 50 limit. They still have the carrying capacity and pure number of red blood cells, but they dodge the heat since they are under the 50 limit. The UCI knows the 50 limit is rediculous, they added it simply to get people off their back and to look like they were doing something about doping.
I hope I answered your question