Well turns out I got a 50# (dressed).
I lined my pit with stone, and started the fire about 1am, and let it burn for 4 hours to heat the stone and build up over a foot of coals.
Wrapped in several layers of burlap, then chicken wire, then tie wire.
I suspended it a couple three inches over the coals with chain, to some rebar across the pit, about 5am.
Checked it at 1pm and it was done. 170-180.
Not everyone was there yet, so put it back in for another hour.
When it came out at 2, it was SUPER juicy, and after handling it a little getting it unwrapped, the bones were just about jumping out of the thing!
Thanks for all the suggestions. I figured I'd circle back and let folks know what worked for me.