ok, so I guess you want to know how to set up UV sapce, no it doesn't need to be solid, and I'd recomend not useing any truespace tools if you can, the later versions are ok for some minor touchup work if you are careful, but for the main job I have been, sence I first tried it, in absolute love with lithunwrap, the most recent free version is 1.3 I beleive, it is the best unwraper EVER, all you realy need to use in it is the decal projection and maybe rarely the cylinder mapping. it's only real down sides are it can only work fully with triangulated polygons, and it doesn't have good suport for cob files, but if you use d3s as a go between format it works pretty damn well.