I know nothing about band wires,but I have used maybe 20 bandsaws and the main source of breakage has always been the join.Traditionally,they were tapered at the ends of the blade strip and then brazed together to reduce the stress raising potential.More modern blades are butt welded and ground smooth before being annealed-it almost always works when done by experienced operatives but i have very occasionally sent a batch back when they were breaking after very little use.You can get bandsaw blades down to about 3/16" wide,would such a thing be any use as it might be easier than learning to put a durable join in an abrasive wire?