If anyone is interested, I have FINALLY finished milling the cedar that I had stripped out of our old solarium and off the side of the house for our remodel. I posted the titular question back in October of last year - it is amazing how little you can get done between the months of October and February.
Ended up having to mill it into lap rather than t&g because of the final thickness - 5/8" - which didn't seem like enough to support a t&g. In order to maximize my yield from the wood I didn't cut to match my joist spacing but rather will biscuit the ends of the boards and let the joints hang in space. I figure the 18 years that the boards hung either in the solarium or on the side of the house induced any twisting or cupping forces to express themselves and the planing took it out. I hope.
It was about 30 hours of trimming, ripping, beveling and rabbeting. I think it was worth it. We'll see in a coupla years. Oh, yeah, wish I had gotten that dust collector - the trips upstairs with the shop-vac every 45 minutes to dump the dust sucked.
App