The transition from HS/PE1 to HS/PE2 was MASSIVE for me. I could easily hold PE1 but when it came to PE2 I was only getting 2-3 seconds (and that's being generous!) Each time I tried it I felt like I was making no progress at all. It was frustrating because I have made great progress in the wrist strengthening exercises but PE2 felt like I was banging my head against a brick wall and I could see no light at the end of the tunnel.
Anyway, today, out of nowhere I managed to bang out a 7s, 12s and 20s hold of HS/PE2 
I couldn't believe it!
Just like coach says, PATIENCE and CONSISTENCY are key to GST
So for anyone else who is struggling with the PE1-PE2 transition, just keep practicing and it will come.