The embedding layer is just a look up table. So you pass an index and an embedding vector is returned. When you initialize the embedding layer, these are just random values. After training the embeddings, you can try the following to check the quality of the embeddings

Check the metric. As everything kept same, the metric value of 69 dim and 35 dim embedding can give you some idea of the quality of embeddings
You can use PCA to visualize the embeddings in 2D space. Although this is not a good approach.