Im using the park wrenches, are there any that are better? As for sizing, how do you match the sizing with the nipple? If it is just by feel, then I think the fit is fine.
for a 14 gauge nipple, what size spoke wrench would you use?
Generally, most DT, Wheelsmith, and Sapim nipples use a Park black wrench. There is NO slop when the wrench is on the nipple.
I use only Park standard or 4-sided.
The Spokey or Park wrenches that are broached at 45 degrees instead of square mark the nips a lot less. It's also a matter of touch. Easy on with the wrench, turn, and easy off. Slow down.
And if it's just the black nipples are causing trouble, have you considered dating Asian?
Try the 4 sided wrenches that park makes (again, like Shiggy said) if you are concerned about marking. They cost a bit more, but do provide a more secure connection.
Anti seize and a 2 sided wrench scuffs much much less than oil and a 4 sided wrench. I only build with a park 2 sided wrench now, the 4 sided one drives me nuts.
Nothing wrong with wanting a decent looking build, regardless if its for you or for sale... a normal spoke wrench should build a clean unscuffed set of alloy nipple wheels without issue. Using anti seize on the threads will make it even more surefire and smooth.