Jon
I will totally agree with you about the evil thermostats. They can have 30-40 degree swings and will also vary at the temp. they kick in. Obviously when this occurs at certain points in the roast the beans will suffer. I've only played with a Behmor for off the shelf roasters and found a similar issue. Some will convert to variac and some will not so maintenance will help a little.
I find BT and ET to each be important for different reasons. BT for the rate of progress and ET to keep below or at a desired threshold of MET (maximum ET). Balancing the 2 with controls and batch size give the best results.

13 minutes to 1C might be explained with the 20oz batch size but 22 minutes to 2C sounds more like the thermostat is shutting things down. My GF uses the same setup you have at our condo, she don't feel the need for a variac, and hits 1C within 9 - 10 minutes depending on the ambient temperature in the court yard.
By the way, the thermostat never cycles off. This is with a ~14oz load. She isn't very big on weighing either, just dumps in a full plastic drink cup and lets her rip. She does lift the co off for ~30 seconds at the very first snap (thanks Jon for that tip a long time ago) and her roasts hits 2C at around 12 minutes. Taste pretty good also.

My Behmor gets the most use these days but when I want to bring out the best in a favorite bean I lug out my co/ufo, variac, 2 Flukes and spend 15-17 minutes hovering over while adjusting ramp and smelling for signs of the roast progress. My use of the variac is to reduce voltage not to increase it. With the thermostat bypassed I can control the the rise in ET to any degree/minute I choose. In the final leg of the roast I'm only feeding the co ~90v but that is in my system...yours will likely be different.

The Behmor is a nice unit, very convenient, but lacks full user control. You can pick the length of the roast, one of 4 preset profiles and play with batch size and voltage only.

Check out Farmroasts blog for what he has come up with...pretty impressive.

Sherman wrote:I can appreciate the desire to "make nice", but if the system was working per se, I hazard to guess that bgn wouldn't have posted in the first place.

Defending myself here; I didn't see bgn say anything about "My roasts used to take 14 minutes, now they take 22 minutes", or "My roasts used to be very perky and delicious, now they taste bland and lifeless", or even "I can't seem to get my roasts dark, they just seem to get stuck at light brown".

Not trying to make nice unduly, just trying to make sure that there is in fact a problem to fix.

Things to measure: times, temperatures, voltages, power draw (kill-a-watt or similar), currents (if you can, but don't go out of your way). Try to figure out what's happening before trying to figure out how to change things.

Not trying to make nice unduly, just trying to make sure that there is in fact a problem to fix.

9min. from start of 1st to 2nd can't be a good thing.

This is exactly what I thought, that second crack was taking way too long. I do enjoy my coffee, but enjoying it and being convinced that it could not get better aren't necessarily synonymous. I started this post to stop myself from just ordering a new roaster. I know I need to learn to measure things (lots of things) better, and have found the suggestions here very helpful. How does one know if the element is 'cutting out' on these turbo ovens?

A cheap digital thermometer will allow you to monitor what is really going on with the roast and tip you to swings in the ET. Other wise you could use a Kill-a-Watt (~$20) to monitor voltage and the current draw of the co. As Jon and Ed pointed out the original thermostats are very crude and temperature swings in a 30-40f range are normal.

Are you using a "spacer ring" between the co and the sc? If so how tall?

The spacer ring on the stircrazy is about 4" tall (so that is the distance between the heater and the beans).