Unlike Ken, this is exactly where I have come in my roast planning using my hottop. I've got a good handle on my bean temperature measurements and delta-temperature ramps during the roast but I don't have a good handle on environmnetal temperatures or where to put the probes. My BT is exactly as RandyG describes on his excellent site. WIth winter roasting I've seen that ET can be significantly lower (20-30*) for a heat input compared with spring or summer roasting. It's not at all trivial to compenste for weather variables. Rather then "acrid acidity" you describe I've seen roast compensations that cause ashy espresso roasts or lifeless muddy brew roasts if the roast profile is not right. Between Max's excellent description of his hottop roast profiles and his use of variable (smaller) loads to get there and your summation above I think there is a good lesson to learn about how to develop a roasting strategy. I also think that it is imperative for a roaster to have at least some skills at tasting the end product and being able to recognize what he/she is drinking.
I believe that this is a significant limitation of virtually any 110v home electrical drum roaster, which will struggle to produce enough heat at room temperature to roast 9 or 10 oz. of beans. If you have to use such a roaster in cold winter temperatures, it is a bit like Sisyphus pushing his boulder uphill, not to mention the fact that it forces you to roast one way during the warmer months and another way during the winter. Not only will this make roasting in winter a chore, it will make the learning curve that much steeper since the variables you face in roasting will be constantly changing.
My own sample roaster lives in my garage. When I first got it, the propane burner supplied with it was horrendously underpowered, plus I had no smoke hood which forced me to roast outside with the roaster on a cart. To say that this was an enormous PITA would be an understatement. I solved the heat production problem by getting a better and much more powerful burner set up for natural gas, plus had a friend build a smoke hood, and the roaster is now permanently installed in the garage under the hood. This allows me to roast at 50 - 55 degrees F in the winter, and has eliminated the cold weather problems I used to have. Still, perfection is hard to come by. I have found that during the winter my gas forced air heating system will deprive the roaster of gas pressure when the house is being heated, which makes roasting well hard to do. As a result, I have to turn my thermostats way down when I'm roasting, to prevent the furnace from sucking up all the precious natural gas I need to roast with
Most people are probably not going to go to the lengths that I did to avoid the problems of cold weather roasting. Nonetheless, if one lives in a cold climate, one should take this into consideration when choosing a roaster, perhaps choosing something that has more heat capacity, in relationship to the bean load demands. Or, one could choose a roaster whose smoke can be evacuated outdoors, which would allow the roaster to be used indoors during the winter.