l'm taking the bathroom sink off tomorrow to do some tiling and thought while l have drained the water l might as well put isolating valves on the hot and cold pipes.Also l want to change the connections onto the taps and put flex tap connections on.Now what size connections are basin sink taps, 15x1/2" or 15x3/4". The flex tap bores are 10mm will this slow the flow of water down out the tap's.