I thinned it again today (didn't measure exact amount of added water) and measured 94 seconds in a Ford cup. The spatter was a bit less than yesterday but not much. When wet, it looked I'd just finished a class in "What orange peel looks like". Fortunately the paint leveled before drying and the results looked pretty good.
I'm painting this bench for my son and he just put down about $90 for a gallon of Duration so buying another product wasn't going to fly. What actually happens when a product is over thinned? Will it not last as long, fade or fail to adhere properly?
Also no mention was made of using a larger N/N set. Would just make the spatter problem worse without having any more air flow from the turbine to drive it?
Thanks again for all the comments.