RE: Solartex and Poly-Tak
You don't need any Poly-Tak.
I just use a clean towel, wipe down the balsa before I start my covering until I can't see anymore dirt coming off. I'm using Solartex on my Fokker DR1 rebuild and I love Solartex! If you don't have tack cloth, don't sweat it because you don't really need it.
Pete