Okanogan - Transforming A-frame - Insulation

[dragonslayer82]

I'm basically using https://relaxshacks.myshopify.com/products/deek-diedricksens-transforming-a-frame-getaway-cabin Deek's design for a transforming a-frame, with modifications to add insulation, and a permanent deck awning off the side, instead of wall lifting up.

Has anyone else used the 1 in. x 2 ft. x 48 in. R5 Radiant Acoustic Insulation Kit - STC 19 (12 sheets) - 96 sq. ft. from home depot? It's reflective on both side of the foam.

I have two ideas:
1. build the a-frame normally, and sheet the outside with the foam, before covering it with corrugated steel roofing.
2. Air space seems to make this really perform well, use a thinner plywood, and glue foam on both sides before attaching to framing, sort of like a SIP panel. This would provide airspace on the outside from corrugated roofing, double the insulation, and still offer a strong wood core.

Is this enough insulation on such a small structure, or do I need to add more between 2x4s? 
If I sandwiched this insulation between thin plywood, could I use smaller framing, as a lot of structure will be provided by the home made SIP's?

[OlJarhead]

I used the pink foam in the roof of my super insulated room.  Basically I framed the room normally and insulated it with R21, then ran the pink foam board over the roof and screwed down another layer of sheathing over the foam.  Then roofed it over that.  This added another R10 to the roof (plus I guess R1 for the sheathing) and then did the same on the walls with furring strips to nail the siding too.

This has served me well!