The ShiftstonedEternal Power Calculator is a deck-building tool that visualizes your odds of drawing enough Influence and Power based specifically on the cards found in your deck.
The thing with Sigvard is... he's like a Crownwatch Squire that doesn't need to be mentored but A LOT more setup. With Crownwatch Squire, a card loathed by most, you get a 1/2 T1 and then on T2 you play Sparring Partner, ideally, to get a T2 4/5 that can't swing, and a 2/2. Which one's better? Yeah, Lifesteal, yes. Think about it. You can also Dragonbreath the Squire for a T2 4/5 that deals 4 damage to a unit. Haven't experimented with that. I mean how do you deal with a T2 Dovid nicely? I don't know... make a 4/5 (exhausted), kill Dovid, get 2 stunned 2/1s? On Turn 2? ... And Crownwatch Squire is a Soldier, right? Soldiers x Mentor? ... No. ... But anyway. Good day. Wishing to buff cards like Dragonbreath, Sigvard... but that's a different story.