that might depend more one how much your sprayin and how long the single line would end up being. i cant think of any reason i would run it the way you have it . your not really taking up any more room with 2 lines and the wieght difference is minimal
I ran 2 seperate lines for 3 foggers like someone else mentioned. I had one #6 line for the big fogger and then another #6 line for 2 and 3. I also had 1/4 turn valves in each line with the big liquid filled gauges from Steve Johnson at each bottle. I never had any issues running the car this way but I did when we tried to use 2 systems with one bottle and a single #6 line. It worked fine in the 1/8 but not in the 1/4. I'm sure the single bottle wasn't helping but I swapped to the dual bottles and 2 line setup and never looked back. I would definitely consider using this type of setup if it was my car.