Despite everyones warnings I have proceeded with a true union Check Valve. Feel free to say I told you so in a couple of months.
My reasons were simple, My original design was to keep it clean and simple. This does that.
My returns are all 3/4" so I went with a 1" valve that way the valve itself it 3/4 inch and this will aid in the flow restriction department. It is fully cleanable as it come apart completely. I have heeded all warnings and will expect a flood if the power does go out. I am putting a ball valve above it so if I'm home and the power goes out all I have to do is shut the ball valve. but in the 2 years I've lived here the we have never had a power failure.
I will ensure that if/when the Valve fails I will post so you can all laugh and say I told you so
Thanks for all your help
Jason