My tip: use the halftone palette feature of openCanvas. Then save your file as a .psd for additional Photoshop editing.
I've used the non-filter halftoning method in PS where you have to switch modes and select degrees, etc. And it's just really more work than necessary and not as flexible and fast as in OC where you can select more patterns than dots and can easily scale them and just brush them in or bucket fill. And you don't have to worry about moire pattern problems.
Traditional zipping? I've tried the stickers. Not as fun as I thought it was going to be. Maybe if one's in jail it's a good way to pass up time.