"He who marches out of step hears another drum." ~ Ken Kesey
Depending on the inks you're using, the 166's will probably put down too much ink and build up quickly. I would throw a flash right in the middle of it. Print the smallest images first, then flash after 3-4 screens then print the rest. I'd go up in mesh count to a 205N if you have roller mesh. If you have some really good wet on wet inks, you might get by with the 166's but they all better be damn good wow inks. If you have image sizes that are all the same size, go from lightest to darkest and since the yellow is consumes a large area, do it next to last then the black. Black ink is usually the worst at buildup, yellow shouldn't be that bad.
Is it xolb with softee? I sure hope not , not a good combo for wow printing I'm afraid, I wish I had better news. But maybe more ink will got into and through the shirt and not onto the next screen since they are wet t-shirt rags. Good luck and let us know how it turned out with the buildup, I'd like to kkow if you had any issues and if you didn't, it would be good for others to see. I have never had an xolb not build up like crazy but let's hope you have better luck.