Im going to remodel my bathroom and install a new Kohler cast iron tub. Im wanting to use a brass drain with the lever pop up style. The question is, The tub drain assembly that kohler says to use is a 14-16 inch, 17Ga. for around $55.00 or I can go to Home Depot and get a Watts 12 to 15 inch, 20Ga. for around $45.00, but the 1 1/2 slip nuts are the only thing thats not brass, which one?