Sparko, for a start I am a novice and you have had advice from others far more versed than I am. Ally flies into extremely inhospitable terrain, so his viewpoint is important although it may not be accurate for yourself. Normally line of flight teaches them the quickest route home, but your geography may be lie Ally's and therefore line of flight may not be the best, pigeons do not usually fly over mountains, but fly round them. Glaciers, I presume are like mountains, so your pigeons will not fly over them. Given your map, I would say you show 4 racepoints. The shortest, your pigeons are able to fly direct as they can with the next race, but after that the glacier becomes an obstacle. Looking at points 3 and 4 it would seem to me that point 1 is the most direct. I presume you have more than 4 races during a season, so decide what races you want to excel at and then train to the racepoint that suits, but given what you have shown, forget the 2nd race, train towards the 1st racepoint and they will navigate that way for the two longest races. hope my thoughts give you something to think about without causing more confusion than you may already have.