I fish only tropical saltwater locations and I fish several days a week. Unless you are using a VERY stiff rod, you do not need to overline. If you are fishing a name brand quality rod, you do not need to overline. If all of your shots are in the 30-40 foot range (impossible when fishing for bonefish), you might overline one weight. When fishing saltwater, always use a saltwater rated fly line of the best quality you can afford (IMHO, Monic is not the best quality). When fishing a tropical location ALWAYS use a tropical saltwater line. The brands I would recommend are Cortland, Scientific Anglers and Rio in no set order. You are probably spending a good bit of money on your trip...don't ruin your fun by usning a cheap fly line...once you get to the water, your fishing enjoyment may depend on your choice of line.