I don't think you'll find a ready made air heating element with temp control.
Edmund Scientific once had a little bit of everything, but they don't seem to have the plethora of Army surplus and whatnot they once did.
You could modify a commercially made dehydrator but it would involve adding a HD dimmer to the heating element circuit and replacement of the thermostat in case the commercially made unit's tstat does not go down to 29C. Many don't go below 38C. By the time you get done modding a commercially made dehydrator, you will have spent 2-3x more than the cost of a homebuilt unit- and the volume capacity will be much smaller than a cheap plastic storage tub.
A link would be good.
I will tell you beforehand though that monkeying around with anything other than a 12/12 cycle for flowering is not a good idea. Lots of ppl have played with all manner of odd flowering cycles over the years; the net result is smaller buds harvested more often. I solved the harvest frequency problem without loss of bud size by running 4 independent systems, staggered by 2 weeks.
Not complicated. The strain is generally unrelated, unless you have a particularly scrawny phenotype that doesn't require watering as often as more vigorous types.
You're looking to water absorbent media when the pots have lost about 1/2 to 2/3 of their absorbed water weight, either by the plants using the water or through direct evaporation.
If using highly absorbent media like RW floc, watering time is 1x at lights on until the flood depth is about 50mm for advanced plants. Plants in wk1-2 can be watered every other day.
If using clay pellets, which hold almost no water, rather must be dampened periodically by flooding, even very small plants will get flooded 2-3x/lights-on with the last watering not much later than 1.5-2h before lights off. No watering is required in any media during lights off.
Maintaining pH and nute strength is also simple but is often overcomplicated by new hydroponic growers, who are tempted to maintain nute strength at the same level all day every day. One should
not be overenthusiastic about making corrections. In particular, one should not add water and fresh nutrient mix to a half-eaten tank of nutes. Tanks should be dumped, cleaned and mixed fresh every 2 weeks but topped up only with plain water and pH corrected on top up between dumps. The reason for this is that you don't know how much N, P & K remain and in what ratio they exist one to the other in a half-eaten tank. Just measuring the ppm won't tell you, either. If you had a device that measured the individual elements (also known as a mass spectrometer, costs a few tens of thousands) and separate bottles of N, P, K & micronutrients, then you could reasonably micromanage your nute strength.
Real people like you & me with $100 EC meters should rely on the chemists at the nutrient manufacturers to get the ratios right- and should
only add nute concentrates to plain water when mixing fresh sauce. Tapwater will be somewhat higher in pH than you need, so when you top with water, you will be adjusting pH downward each time. I would not bother topping up tanks every day- you can top up and correct pH 1-2x a week. You should be adding H2O2 50% grade to your tanks at 1ml/L every 3-4 days, so you can top up at the time if you like.
If you can hold these concepts in mind, you have all the experience you need to properly manage your nute tanks.