Some people wrap their birds, hams, etc. in vinegar-soaked cloth or a stockinette to prevent blackening but I do not have that problem. That seems to happen more with lower temps (I don't do turkeys low), too much smoke or poor fuel management.
I use cheesecloth as a basting mechanism with a liquid (i.e. water-based) baste that has enough fat in it to provide flavor and color. On a whole bird it will slow down the cooking of the breast a bit so that it doesn't get done too soon (dramatically sooner than the legs/thighs).
I use white wine, chicken stock, a little honey and whole black peppercorn, parsley stems, a few sage leaves and a thyme stem or two. To this I add some unsalted butter as a flavor carrier and I heat simmer all of this then let it cool a little. Tripled cloth goes in to soak and I lay it over the breast aboout 20 min into the cook. I baste the cloth--over it and under it--twice or thrice during the cook and remove it when it cooks itself and is hard. The skin will color under the cloth and the color evens out when the cloth is removed toward the end as well.
This is not necessary and I have done many turkeys without cloth, but I prefer to use it on whole turkeys because imo it evens out the finish times between the two meats. I haven't done it on breasts alone but I rarely cook breasts alone.
