I can’t offer much advice on recruitment assessment days apart from the fact it’ll be a straight forward interview and sim in either Dublin or Stansted.
Unless you’re on a mobile (floating) base contract, you’ll be on a 5 days on / 4 days off roster. One block of earlies / 4 days off / one block of lates / 4 off etc etc.
For Direct Entry Capt you can have your choice of contract (ie directly employed or agency) and pretty much your choice of base. They may not offer you the base you want but if you make it a condition that you won’t join unless you get it, you probably will.
You’ll fly typically 800-890 hours a year and it’ll be a mix of 2 and 4 sector days. Back to your home base every day with occasionally a week out of your home base which (if you’re directly employed) will mean hotels and transport provided by the company. If you’re an agency contractor you have to sort out accommodation yourself and you receive €30 per scheduled block hour additionally to pay for hotels etc.
Mobile contract is a 5/5 roster and you’ll change base frequently.