Hi Phil,
Good to see you made it
I use the box for about 1 hr at a time, although Obviously at my age I may unintentionally leave them in for 2/3!!!! : Not that I'm forgetful, it's just that I don't remember!
I use a 25 watt bulb from a fridge, it definitely gets hot enough.
The oil is dry by the morning for recoating. Prussian blue is the painful one! It takes time to dry, heat or no heat!! After 2 weeks it will still be glossy, Then one day after it will suddenly go Matt, weird or what!!!
One more bit of advice, I work on 5-10 figures at a time, if you put these aside and leave them in the hot box whilst drying others, they will after a couple of weeks go flat-flat, they lose the sheen that gives them the 3D effect.
If you have any troubles just ask.