Hi,
1h 45mins is plenty! I have done about 160 Schengen to Schengen transfers trough HEL with 40 min transfer time, and so far my I have managed to miss 4 fligths. This figure includes all flight delays

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My record is 20 minutes from the non-schengen(G33) to schengen (G17), altough you have to leg it a bit in order to make it. This includes the safety inspection and passport control queues. If you have non-EU/non-nordic passport, I would add about 15 mins of passport queuing on top of the 20 min minimum.