Thanks for your response Bcspark. Am waiting for the Victor 86B DMM to arrive end of month so that I can hook up and log into the pc. Currently my 1 kg roasts on the turbo oven are tasting a bit flat/dull due to the long profile ( 25 min), so it's back down to 600-700 gm batches. As soon as the new roaster cover and heat gun goes on, the aim is to get the roast down to 17-18 minutes for 800gm-1 kg loads. How the silicon rings will last with the extra heat input, it will be a matter of finding out. In the past, have had silicon rings bubble and disintegrate when I modified the last turbo oven by removing the heat guard and angling the fan blades. My current oven (Homemaster 1400 watt) is with the guard on but with four holes cut out as per KK,s method. Interesting times ahead, and reports will follow. Lacehim, I agree TOs are not created equal. If for any reason the HGTO gives unsatisfactory results, I may very well try another turbo oven, perhaps the Rank Arena such as yours. Are they halogen or element?