ok, difference in terminology maybe.
if your flange bearing is a single ball, with a big hole thru the ball, that allows for some degree of auto alignment, then that is probably fine. the big problem with those is how much axial load can they take (you have to have a separate thrust bearing), and the way they place their mounting bolts in single shear (high wind tries to cut the heads off the mounting bolts). by design, they prevent the shaft from being held at a right angle to the thrust bearing, causing thrust bearing to wear on edge.
heavy walled pipe around bronze bushings may be better. pipe is unlikely to bend much during welding, so you dont need your flange bearings, the bronze has a much greater bearing surface, is cheaper, and can be reamed as a pair once installed, if you need to. you can also get a bronze thrust collar.
i would move the thrust surface to the top of the pole, makes fabrication of the pole much easier, since you dont have to weld a flange at just the right height to the pole, you just drop the nacelle over the pipe.
in order for that to work, you will need a washer welded to the top of the pole, and to the top of the tube in the nacelle. this will make removing the top bushing harder, but maybe you can find someone with a really long cape chisel 
resist the urge to use torrington needle thrust bearings, or any other kind of roller/ball bearing, unless you are very sure of tight manufacturing tolerances, and are using very hard materials as backing races. those types of devices are high-load and low friction, but only if all the balls are routinely sharing the load. they wont be in a yaw bearing made of pipe that faces the same way most of the time.
as far as the mainshaft, yes. move it down on the side of the nacelle. make the top yaw bearing as far above the mainshaft as the lower one is below it (or even a little higher) the overall lateral loads the yaw bearings see are not reduced, but the 'twist' that attempts to destroy their edges is reduced by spreading them away from the mainshaft.
switch to square tubing over angle iron. can be thinner and lighter for same strength, cost similar. figure out what you are doing with the tail. that will change the design a bit, especially if it is a fixed unit.
did you ever watch scraphead challenge/junkyard wars? the neandertal solution always won. (black powder cannon shooting cast iron balls with fixed breach beats smokeless powder lathe-turned shells free breach, blimp beats fixed wing, range rover with prop and rudder beats transit van roof pretending to be an airboat, sealed container with batteries and wet electric motor and divers hanging on beats carved out, ride inside air powered belly tank)
unless you have a fully equipped high-quality shop building this whole thing for you, you are in a neandertal problem, use the neandertal solution. bronze bushings, pipe and washers, not rollers and flange bearings.
allan
