I have been wanting to try making the same Fukiya style darts from plastic film of some sort. In the local Soriana store here (Mexico's equivalent of WallMart) I found some plastic xmas wrapping paper. It was like a thick Saran wrap without the stretchy properties. It was so thin that even with multiple layers it had no real strength to it. But even as you stated, when the darts absorb moisture which these would not, I think there would still be a lot of condensation on the inside of the cone because the cones are so long and deep. That could be a little fiddly trying to dry up that condensation when air cannot readily get to it and help in the evaporation of it. The Fukiya style have shown great promise. They would be wonderful if not for this moisture problem. I also noticed the accuracy deteriorating shot after shot with more and more moisture being absorbed each time. Yet once dried they resumed their good performance. I for one don't want to be wiping out my bore every few shots or having to lay out my darts to dry but they are sweet darts when first shot and still dry.
In the photo you can see two types of skewer darts. One type with plastic cones and the other with duct tape. The duct tape ones have a stem of the shaft protruding past the end of the cone. I really like using these darts with my crutch tip mouthpiece as they allow me to place the dart into the barrel more consistantly than without that stem using just my fingers. I have not noticed any difference in accuracy between the duct tape darts with the stem vs the plastic cone darts without. Also, the cones stands up better as it is not being handled so much when the dart is loaded as the dart is being held by the stem and not the cone. Has this style ever been proven to be more or less accurate than the same dart with the cone farther back leaving no stem?