Im no Norm Abrams , but you can use the standard 3/4 pine found at HD or Loews ...A 10 footer 1x12 will do . Just make sure you use a decent ply for the baffle and set the baffle deep enough incase you decide to use clips, so that you can install a front board or whatever to protect the speakers in transport... No need for precise dimensions.. I believe mine is appx. 32 tall,20" wide,12" deep..If you checkout "rocket cabs" on eBay , you should be able to roughly eyeball the design .. Dovetailing the pieces is a good idea, but I don't think its how HT does it.I'll see if I can find a template for you in the meantime.. I'm about to borrow a buddy's Leigh Super 24" jig and see if I can bang out a couple nice cabs this summer.