re: Hanging Christmas lights help

Im not sure why flat rolled would make a difference. On regular shingle roof I just use plastic hangers for Christmas lights from any store. They generally last 2 seasons. When multiple hangers are put close together it will allow the strand to be pulled taught like at the ends of the strands.

I buy Christmas lights on the roll and save the roll. At the end of the season I roll lights and plastic hangers on the roll (in reverse). The first year it took me about 3 hours to get hangers figured out but now it takes me an hour to string the entire house including bushes.

Eta: these are similar to what I use, you can orient them many ways for different size lights. You can get a box of 100 for like $10 at Walmart