I usually wait about a month to do the first spraying, and if I'm getting rain and look like I'm gonna make a decent crop I will spray again at about 60 days. But my fields are all old and have every weed imaginable. Most places you can probably get by with one spraying.

I don't think you need to spray if chufas are still coming up. Weeds aren't really hurting anything until they start competing with the chufas.

I have heard of people using 4 oz of Milestone but I've never used over 2 myself. It is possible to damage them with most any herbicide, but the combo of the 2 mentioned here does less than anything else I've used. You are most likely to get damage in drought conditions, so you can likely get away with using a lot this year.