I am not sure whether this testimony really helps the OP (he probably doesnt need it anymore anyhow). Going from 1st level to PSG in a few month is not achievable with one clinic.
It does make a huge difference whether you ride with somebody for a weekend or on a regular basis…
I have 2 clinicians coming to my area who I ride with. One is coming every 3 months and one is coming every month or every other month.
Honestly my progress started only after I rode a couple of times with them. At that point they knew my horse and me and what we needed to work on. The first rides were nice but they would not have gotten me anywhere as a single clinic.
I think its really the continous instruction which helps the progress