Happyhopper,
Another Treacy patient here, and when it comes to the actual hip, I couldn't be happier. I too though have sensitive muscles, although I didn't know this until the op was done!
I'm battling to get them all working normally again and i've a long way to go, but my advice would be to do the exercises given to you and do them as often as you can manage safely.
Now, Mr Treacy doesn't prescribe PT after his surgeries, though in my case it's been proven that would have been of HUGE benefit to me as my hip flexors/psoas have pretty much hardened to a rock and have caused many further issues that I just wasn't prepared for.
I've been attending a chiropractor 2x weekly for deep massage and about to start intensive hydrotherapy, at Mr Treacy's request, next week to help me regain strength and ROM. The trouble is this has all come about 3 months too late and the damage has been done and it's going to take a long time to get back to normal.