They won't all be perfect right angles, and they won't all pull up right against the pole. What you really care about is hole-hole spacing (can't assemble it otherwise), approximate centring on the pole centre and consistent depth of the pole half-hoop. The rest either pulls out in the wash as you tighten, or doesn't affect the function. You can live with a small gap between pole and bend (i.e. a slightly obtuse bend), but you care far more about assembly, and about getting the final axis through the centre of the pole and the bolts being at a right angle to this.