Donny and Jerryghr just opened my mind and ears. Both wonderful examples which I shall keep and refer to. Many have offered excellent advice, but to hear what you all are talking about opens a whole new world. In Donny's rendition, I can see playing off the blues scale. I often ad lib the melody staying in the structure of the scale, this isn't any different, just applied in another way.

It's funny how I have heard comping for 50 years but wasn't listening, because I wasn't trying to do it.

I once was blind and now I see(sort of).

Thanks all