I pregerminated Black Jack Bermuda seed last year. For me it was right around the 7 day mark before needing to spread it. You have to be ready to spread that seed at any time around the 7 day mark as it will become a tangle mess of growth in no time.
As for the technique, I followed a youtube video but this is the jest:
Get x2 5 gallon buckets and a paint strainer mesh. One bucket will sit inside of the other. The inner bucket gets the mesh and needs a bunch of drain holes drilled in the bottom. Weight out your seeds and put it in the mesh in the inner bucket. Finally place the inner bucket in the outer (unmodified) bucket.
Fill the buckets with water for 24H and let it sit. The next day at least once a day from now on, pull out the inner bucket to strain water. Place inner bucket and soak with fresh water then drain again. The seeds no longer need to be kept submerged in water, they just need to be kept damp. I was doing the water rinse in the morning and in the evening. The seeds lived in the garage.
One thing to note here is that Bermuda seeds have a heavy coating on them and the first couple of rises will have a strong coloring so dump it where you wont care about the color staining.
For spreading it, I mixed it with milorganite.
Youtube video reference: