OK, but to Anthony's point, is the flow from the combination of the two -6 lines greater than, or less than the flow potential of the single -10 line. If it's less, then you may want to change those -6 lines to something larger to remove the "constraint" and maximize flow up to the carb. So, answer may be: change the -6 lines to something bigger and move the regulator up to the carb end of the -10 line.
Of course the simpler answer is to actually figure out the flow rate you're getting and determine if that is indeed sufficient before making any changes. Could spend a lot of time and money based on theory when in fact there isn't an issue - which I always find myself doing despite this advice
I think I have some weird need to have more projects to do on the car vs just going and driving it
