I have applied colored domestic tissues over silkspan and polyspan as a trim, with only clear dope on top of tissue.
Takes a bunch of coats to fill the tissue.  Keep it out of sun as much as possible,  because it fades easy..
 

Yeah,
Like I am the only one in this conversation that complains about weight! lol
I covered the Avenger with Polyspan first, I LOVED it, it filled faster and streched, * shrunk* nicely. However after I had it all filled and ready to start sanding, I discovered that the psuedo I beam wing on the Avenger was pretty weak torsionally, I could impart a pretty good twist in it with out much force. So after much deliberation I decided to cover it over with slikspan which then made the wing totally strong and rigid.
The poly span is much more puncture resistant than silkspan. so I ahve the rigidity of the silkspan, with the puncture resistance of the polyspan. Were I to do it intentionaly though, I would apply the polyspan, brush one coat of shrinking dope on it, then apply the silkspan and dope it. That way I think you could save a bunch of weight in the long run. Thats my experience, for what its worth.