Don't think it is too much since the crickets will eat even the seeds that don't germinate. Allow sometime for the plants to grow at least to two or three inches. Water them lightly since the bottles tend to retain a lot of the moisture. Now it is the time to place the crickets. You can buy crickets at bate shops or petshops.
Males have two spikes on their tale while females have three.
Place a bottlecap with water inside for the crickets to drink. Make sure the small ecosystem is not too wet inside, otherwyse wait for it to dry a bit before placing the crickets inside. This means they are laying the eggs. If they don't do that within the two hours after you place them in, add in a couple of males to the bottle. I have placed up to five adult crickets in the bottle just to start the ecosystem.