I used the 2.5 mm tube with a 2.0 rod to make the vent pipe on top of the main cabin roof, filed the rod to get a 90 degree bend and then soldered that elbow to a short tube riser and the longer horizontal pipe with a soldered support piece. Having the old photo of that helped with the grey color as I originally had blackened the brass and had to paint over that. Fairleads that you mention may be the future now that you have mentioned those. Most fairleads are not much more than beads at our scale. Those would possibly be 1.5 mm at most. Previously I used a single turning block for that use leading the fall up to a belaying pin. I have seen that on Bluenose II deck photos also. I'll keep a tube in mind when as I want to get all of the deck items in place that I can now before access is obstructed. Rich