Ooops, I left you with half an answer. I apologize for that. Are you using Photoshop to prepare your images? If so, I can give more info that will hopefully help. Keep in mind that I use this method for all my halftone images that I plan to screenprint, but I don't actually use transparency paper at all and the mesh I use for my screens is either 10xx or 12xx, so I don't know what type of results you'll get.
First off, don't use the halftone listed under filters, as it's not a proper halftone.
Once you've got your image in black and white (and grey), change the image mode to bitmap. (You may need to change the mode to greyscale first, if it's in RGB or CMYK, and then change it to bitmap.)
When you choose the bitmap mode, a dialogue box will pop up with settings for the halftone. Again, these settings work for me using regular paper that I create a makeshift (and much cheaper) transparency from, and typically 10xx mesh fabric.
I use the following setting for halftones:
Output: 150 pixels/inch
Method: Halftone Screen
When you choose Halftone Screen as your method, you'll get another dialogue box for Halftone Screen settings. I use these:
Frequency: 30 lines/inch
Angle: 25 degrees
I never change the frequency, but I vary the angle from anywhere between 20 - 30, depending on the results.
Hopefully that a lot more help to you.