I remember your first experiment last year when you first found out about the breathing bags. I believe it is impossible to do this the way you are attempting. The egg window I believe is the only way to get a successful result. You should start with an egg, cut a window with something precise, a scalpel maybe. Look for a bulls eye after cutting the window. After you find it, wrap the egg in a sterile kordon bag, covering the least amount of egg shell that you can. Do this in order to ensure you aren't blocking pores on the egg. Then you should place the egg in an incubator and incubate it as you would a regular egg. Except maybe I would add a bit more humidity for that egg because of possible rapid moisture loss due to the kordon bags letting out too much moisture. If you do this successfully, the veins will grow over the window and all over the inside of the egg. Lockdown as you would a normal egg, no extra care required. The chick should pip and hatch normally. Its also heavily advised that you do this with a control group of normal eggs to compare data against.