The Humminbird Lakemaster Minnesota card does not cover LOTW. You need the Wodds/Rainy card or you can now buy just individual lakes loaded on your own blank card.
And unless its changed? the lakemaster does not cover all of the lake yet, where we go in the Angle you lose the map up the end of the French portage. Maybe it has changed
V4 is what Humminbird is selling now, but the description refers to V2, so who knows what has been added. It certainly would work for your Helix, but why would someone be selling it for $50? Be careful.