I am ready to install the last leg of gas line that will supply a 30" free standing gas range. The supply to this leg so far is 3/4" black iron. It seems to me that, given what's readily available, the most efficient valve and flex connection line combo are both 1/2". Since I have not yet found a 3/4" to 1/2" gas valve I have the option of using a 3/4" to 1/2" 90* elbow in the final upward (through the floor into the kitchen behind the stove) supply leg making the final connections easy and with minimal adaptors or joints. My question is this: Would there be any issues in doing the reduction to a 1/2" supply in this final section? The flow through should remain adequate for the needs of the stove? Or is it better to keep everything 3/4" right through the valve and use reducers to make the final 1/2" connections. Just looking for a few pros/cons, or what the norm is before I finish.

Thanks to all.