Boy, are you in luck I don't think there is a hot plate that will keep emulsion temperature within one degree, no matter how much you spend on it (but I'm sure someone will come along to argue otherwise). The answer is to use a waterbath jacket. A waterbath ( set on even a coffee mug warmer or a scented candle melting base will more than do the trick. I keep a plastic spoon in the emulsion along with a thermometer. All that's necessary to control temperature precisely is to pull the emulsion out of the waterbath and stir with the spoon until the thermometer registers the temp you want, and then pour/coat a plate. Set the container of emulsion back in the waterbath until the next plate. Note about the illustration: the probe in the lid of the Pyrex dish is attached to a kitchen grade Sunbeam oven thermometer attached to the wall.

If you really want/need to be fussy with the temperature, you can keep a bowl of crushed ice and thermos of hot water handy to tweak the waterbath temp, but I've found that the preset temperature on the simple warming bases to be quite consistent. If you start with a given waterbath temperature, it should hold just fine throughout a typical coating session.