I'll try to answer your questions as good as I can from my own experience.
First of all, it's no rocket science! Working clean is the most important thing IMHO.
1. What kind of cheeses are you making? There will be a significant difference between blue cheeses, white mold cheeses and rind washed cheeses. But also (semi-)hard cheeses can have a variety in taste, also depending on how long they are aged, how they are pressed, what herbs you add etc. etc.
2. Depends on how you work. Working au bain Marie you have to add hot water. I'm using an electric kettle and from experience I know when to switch on and off. Also working au bain Marie is a matter of experience. And log what you are doing, otherwise you will forget.
3. Again, it's no rocket science. Generally you can say that the smaller the curd, the more surface there is for the whey to drain, so the drier the curd will become.
4. One of the charming things of artisan cheese is the variety, also in what is supposed to be the same product. When I buy cheese at my local cheesefarm different batches of the same Gouda of the same age will taste differently. And what is causing that difference? The combination of differences in temperature, volumes of additives, morning or evening milk or mixed milk, temperature in the storage, differences in the brine etc. etc. And what will always taste the same? Cheese from a factory because everything in computer controlled. If you really want to be more accurate buy a digital thermometer. I have one that also has a clock, so it's easy to control how long it takes to rise 1 degree...
I wish you success, don't be afraid to ask and to experiment.