I just started doing my own E-6 and had heard similar reports about the necessity of heated drying. Kodak's tech pub simply states not to dry the film above 140 deg. F. If a minimal temp was required to stabilize the dyes I tend to think Kodak would mention it since any improper processing and resulting stability issues would reflect poorly on their product. Perhaps the idea of a high drying temp is from years past when E-6 final rinse contained formaldehyde. Its possible that the new chemistry doesn't require a higher drying temperature but I'm sure someone with more knowledge on the matter will chime in.