Gorgeous! I'm helping to organize a Hollow Crown poster competition - would you be interested in creating something to enter? The contest is to promote the series, Henry V included! Details are on our Facebook page: [link] Hope you'll enter!
That would be great! You may not need to worry about resolution as much - the judges probably won't be viewing at a size large enough for resolution to be a critical issue (certainly not a bigger issue than content and artistic value).
The submission deadline is the 5th of November so it's a bit less than a month away. If our FB page doesn't give you enough information, please feel free to email firstname.lastname@example.org