@ascentale yeah the taste is 50/50 dependent on variety of apples and yeasts used. I have "the garden mix" - what I can get my hands on all juiced together. It gets quite interesting sometimes, but the sour to sweet apple ratio is something I always try to balance somehow, yeast can be managed easily.
PET bottles hold a lot of pressure before they explode (yes they don't leak that much) - if I remember correctly it is something like 6bar. And they aren't the best choice for aging, if I put something in them it is usually gone in 2 months after it is good for drinking.
Only thing that you can do to manage the carbonation at this point is temperature - cool it down so it holds more CO2 in the liquid form.
I try to plan bit more in advance and still end up short on glass bottles so I don't judge the usage of the PET ones. Also I use it all the time for beer that I know I will drink in a short time, you just have to know the limitations of them and plan accordingly.