For the thin strips I would use Aspen or Poplar. I believe that they are different species but around here both names are used for the same tree. If you have lots of money we sell you Aspen, regular folk get poplar. It is very white and I think lighter color than basswood and as soft and about the same weight. I don’t know where you are located but it is very plentiful around here. I am going to put thin lines on the deck of my next build. I am going to plane a cedar board to 7/16ish and plane an aspen board to 3/16ish and laminate them together. Then I am going to rip 1/4X3/4 inch strips frm the laminated board. I don't know how it would bend, but on the straight runs it should save some time. As suggested in an earlier post I will not cove and bead them because sanding will be inconsistent and the lines will turn wiggly.