I use the following stuff from BalsaUSA, it irons on and can be painted. It is tough like Koverall but can iron down to wood. The Natural finish can then be primed and painted.
I stopped using Dope a long time again and have been fiberglassing models ever since. But the model structure is open I use this stuff. You use an Iron and heat gun just like you would with iron on film.
Some guys use Polyspan with Dope with great resultshttp://shop.balsausa.com/product_p/556.htm