In terms of submitting, once an issue is released, we delete all submissions and start over for the next issue to ensure a fair chance for all entries. The best time to submit would be any time between when the current issue is released and the next NT date.
For example, NT 1004 was published on March 22nd, so any time between March 22nd and the next issue release date (April 5th) would be fine to send in your submission