Ok here is the choise I have to make.
1. Fly to Helsinki. Take the 2hr boat over to Tallinn for the day and 2hr boat back. The the next day take the Overnight boat from Helsinki to Stockholm.
or
2. Fly to Helsinki. Send the day and the take the overnight boat to Tallinn. Spend the day in Tallinn and then take the overnight boat from Tallinn to Stockholm.
Any help on this?