The deckbox is an Ultimate Guard Twin Flip'n'Tray, as seen in the proof photo. The mainboard fits into one section if you squeeze the cards in, and the sideboard fits comfortably in the middle section. If I had used perfect hard sleeves instead, then I'd likely need to use more than one section for the maindeck, with the remaining section for the sideboard.

For the four layers of sleeves, the first two layers are your standard double sleeving. Layer 3 is KMC Character Guards, which are $7 for a pack of 60 as of the time of this writing, so an additional $14 to get your 75+ sleeves. Layer 4 is KMC Strong Hard sleeves (NOT Perfect Hard), which are tough to find. As of the time of this writing, the ones on ebay are going for about $25 for a pack of 50, so an additional $50 to get 75+ sleeves, though since it's ebay that will vary a lot based on which sellers are listing. That's roughly an additional $64 on top of whatever double sleeving costs.