Slightly OT: Reserve much more time if you connect to *A flight, donīt have your luggage checked through and donīt have a boarding pass. The *A trasfer desk airside can be unmanned (it is unmanned before 8:00 AM - a very aggravating feature) and the TI check in area is a total mess most of the time, especially if it is holiday season. In case you (are desperate and) have to use a *A carrier from HEL, do check in online, PYOBP, and have carry on luggage only. Then you might not miss your flight.
Exactly. HEL T1 is horrible. Security queus on rush time are long. It is sad that Finnish press don't bash *A and T1 sitution but only AY. And combination of T2 and AY works way better.