Vcone meter- wet gas metering application

We are installing Vcone meter for wet gas metering on wellhead flow lines. I need help from flow metering expert to advise:

1) Is there a pipeline straight run requirement (upstream and downstream) for Vcone meter as per ISO5167? Most vendors specify 3D upstream and 1D downstream.

2) Can I use the DCS algorithm for the wet gas calculations or a dedicated flow computer is required?

3)Is there any specific software requirements for the wet gas calculations?

Thanks for any advice.