Poly Spray Foam insulation

Hello, my first posting here.

I live in Soldotna, Alaska and building my house here. I have a 24x36 house with attic I am building. I will be ready to begin insulation soon and I have always previously used fiberglass insulation, but for Alaska I think poly foam is better fit as my neighbors very large shop has one tiny heater and stays warm even in -20 F. Poly foam just seems to fill all the holes that fiberglass cant compete with. I am going to go with poly foam in my place, I have 8' walls and 1000 sf of wall space to cover (2x6 studs). I do not know much about it other than you need at least 60 degrees to spray it and for residential home insulation you need closed cell spray. I want at least r-19 equivalent and the kits come with 1 inch at either 600BF or 1000BF per touch n seal kits. I am thinking I will need to at least triple that because I know 1 inch is not enough for the cold climate here, maybe even quadruple. I am thinking I need about 3,000 to 4,000 BF of spray foam to adequately insulate the house. The attic I am going with the blow in insulation at Home Depot. I built my trusses by myself and they turned out pretty damn good, I like to save money where I can and I usually do a good job because I know I have to live in the house haha.

Thanks in advance, any advice is appreciated. I can help if anyone wants to build their own trusses.