Re: attaching wood furring strips to inside of hull
If the insulation is 1 inch the strips be 1 inch softwood. I like backcutting on table saw if a lot of curve and precut foam and use it for spacing vertical (no spiling) Horizontal ceiling can be spiled or not but beading looks good. I've found red cedar too soft and shows finger nail cuts. Yellow cedar is good but a hard wood is better It's your man cave so budget is not important. Lots of different glues work good.