Doesn't really matter what is used when you are practising smudging, all that matters is that you practice
you have a nice flow going on here, it looks like you have darkened the edges with a soft brush(not sure if you have) but incase you did its not a good idea to do that in a smudge tag. The main reason for that is because it looks out of place, its better to smudge darker colours to get that edge darkening.
The way you have smudged this looks much better than the samus tag you did, its more just fine tuning what you have done by adding more smudge layers on top and using different blend modes. There are still a few wayward lines and a few that are a little bit out of place, but its great to see good improvement