"The first 25 hours or so are the most challenging as this is building up the basic/fundamental general handling skills"... ready to get you in to the circuit.
Crikey, assuming one hour per lesson that's an awful lot of flying just to get you ready for the circuit. I would be a bit suspicious of a school that tells you that.
To the OP. It depends on what you are like as a learner. The faster I cram stuff in the better for me. Not everyone is the same obviously so you have to see what pace suits you, it's not a race. Try doing two lessons a week, if that is too much then do one. What you don't want to be doing is relearning skills that have gone rusty every time you go for a lesson.
Headsets. Well my instructor told me that there are around 200 different infections you can pick up off a headset. I bought my own the next day. I use DC 13.4's and a cheaper set as a back up. The DC's are fine if like me you do around 6-8 hours a month. If I was doing much more than that I think I might go for the Bose or Lightspeed.