Plastic tanks. Maybe that still helps though.
My laptop computer is a regular toasting oven (a few years ago, a dermatologist from our local hospital published a paper about how the long forgotten phenomenon of erythema ab igne, a.k.a. toasted skin syndrome, - not uncommon when people still had to sit close to fires and stoves to keep them warm in winter - had made an unexpected return thanks to laptop computers), so maybe if i turn it upside down and put the tank on it?
Thanks for the suggestion.

14 C would be o.k.?
I understand the idea is to exhaust the developer, leaving oxidated developer (and what not) in the emulsion to shield against overdevelopment? If so, perhaps i should just let it sit for an hour extra (was planning to have it - HP5+ - sit for 1 hour in 1:50 diluted Rodinal).