Reworking old sketches of the Great Plains horsemen

Salve,
I am practicing with different 'brushes' and 'pencils' in MyPaint and I have started reworking some old sketches  of the Great Plains warriors

I must add that three of these sketches were based on the books by Thomas E. Mails in my collection - biography  he was a great man whose work and art I greatly admire -   Mistic Warriors of the Plains  and ''Dog Soldiers Societies of the Plains'' - Mails Dog Soldiers