dual 10lb bottle plumbing

Ok i have a carb plate setup that i run a single stage on I purchased a dual bottle bracket and want some recommendations on how to plumb it i would like to use a -4 Y that way i could just open one bottle and when it runs out close it and them open the other. Is that going to be a problem because i would be back feeding a closed bottle? Any help would be great i have a few more main lines and could run two if needed but long story short i dont want to have to unhook anything inbetween bottles, at most i could close and open the tank valves is there a better way? Thanks

Use the y, just open both bottles.same.time. more consistent pressure and easier to tune more consistent E.T's

That would be perfect. Thanks

How much are you spraying?

Oh just two stages. Nothing crazy. Enough to get the job done.