Its commonly known that Business Reward seats on Aer Lingus are hard to come by/ people have said difficult to book unless you are using the almost-a-year-in-advance window.

Having been preparing to book a NYC trip for my wife's 40th birthday in April and monitoring the situation regularly for a long time I've found out the following:

* Business seats are released for reward bookings EXACTLY 80 days in advance for flights DUB-JFK, JFK-DUB, DUB, DUB-EWR, EWR-DUB
* Business seats are released on most days, for most flights and numbers released vary between 1 (least often), 3, and 5 (most often)
* Certain days of the week you can be unlucky and NO business reward flights are released. These seem to be predominately Wednesdays and Fridays in either direction
* If none are released on day 80 NO more are released later
* I was lucky to snag 2 Business Reward seats DUB-JFK on 20/04 April (my wife's actual birthday). But zero JFK-DUB or EWR-DUB Business reward flights available on our planned return date (Friday 24/04). Looking at the cash prices for business for that day - they are through the roof and very few cash ones available - so lots sold or a block booking
* Other routes demand is different (e.g., there were Biz reward flights available on 24/04 IAD-DUB-MAN but we decided a flying visit/few hours sightseeing in DC was too logistically difficult and tiring)
* There was plenty of business availability for Saturday 25/04 JFK-DUB-MAN but unfortunately can't change my plans for both childcare and cost reasons. have ended up booking economy JFK-FRA-MAN via Lufthansa as a good 2150 departure time, airside transfer at FRA and Lufty lounge access at JFK and FRA via Amex Platinum

Hope this is helpful for anyone trying to book business reward seats on Aer Lingus.