Well - I stalled on the new roaster design, but I finally have continued with the halogen SC/TO.
The halogen TO I have came from Aldi's ~$30 IIRc0, is rated at 1300W,and aside from the heating element and plastic knobs, is close cousin to my conventional 1430W GG. The relay based thermal cut-out had to be defeated, otherwise it kicks off in the middle of a roast.
So among differences - the old SC would release smoke between 1st & 2nd crack, but the halogen unit seems to burnoff the smoke. My garage is a LOT less smoky. If I stall the halogen heater to add some rest time late in a roast - then I get smoke.
Same beans take 30-40 seconds extra to hit 1st crack in the halogen system. I suppose I could attribute that to 1300W vs 1430 watts.
The resulting coffee is notably brighter, a notch more brightly acidity, despite having very similar color and a longer roasting time ! It's on the edge to 'too acidic' and holding onto varietal flavors of nut & fruit well - and this is a touch into 2nd crack.
So far the glass on the TO is only discoloring/fogging on the OUTSIDE of the springform holder, and a cursory inspection the halogen element looks clean. I've only put ~4.5lbs of greens through it, but the halogen heating method looks very promising so far.
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As an aside I rather gave upon fluid-bed after correcting my calculation of re-coverable heat. Too inefficient. That leaved induction heating and various forms of light/EM.